The Fireless Cooker

One of the earliest mentions of the fireless cooker as a device suitable for the home cook came in the form of a newspaper account of the 1867 Paris Exhibition.

The Paris correspondent of the Times has lately called attention to an apparatus for cooking which he has seen in operation at the [Paris] Exhibition, and which really seems capable of bring about, not only a saving of the most valuable qualities of food, but also of fuel, water, time, and money. The invention is simplicity itself, and as we have personally examined and tested its powers, we are able to give a description of the modus operandi. We have first, then, a wooden box about eighteen inches square, and on raising the lid it is seen that there is a lining throughout of black felt (enclosing a thick padding,) leaving an aperture in the centre, which contains a round tin box. We were courteously asked to name some viand for illustrating the use of the apparatus; and having selected a promising-looking chicken from the nearest poulterer’s, it was placed in the tin box (which is really the cooking vessel, and has a lid like that of an ordinary saucepan,) a sufficient quantity of cold water was added to cover the chicken, potatoes and rice were put in, and the cooking vessel was then removed and placed on a common fire. As soon as the contents had been brought to a boiling point, the vessel was quickly removed from the fire and dropped into its nest in the box; a wad of black felt was placed over it, the box lid shut closely down, and the box carried away to that part of the room furthest from the fire. Two hours afterwards the box was opened, the wad removed the cover of the vessel raised, and a most appetizing odor gave promise which was amply borne out. The chicken had, in this automatic fashion, been cooked to perfection, and it was evident that the loss of flavor and delicacy by the ordinary process of boiling had been entirely done away with in the present instance. Potatoes and rice were equally satisfactory. p. 193

Richmond Medical Journal. March, 1868. Volume V, Number 1. p. 193-194. The Medical Heritage Library. Available at: https://archive.org/details/richmondmedicalj05rich.

Some further context was provided in a report from 1913 which also referenced another name for the cooker — the hay box, and a place of European origin — Norway.

The fireless cooker is, I believe, a Norwegian invention. It was first brought to the attention of the public at the Paris Exposition of 1867, where a wooden box lined with wool and felt was exhibited under the name of the ‘Norwegian automatic kitchen.’ Food boiled on a fire for a very few minutes continued to cook slowly when placed in this box, and after two or three hours was in excellent condition for the table….At the same time improvements were introduced; instead of being made entirely of wood, as at first, cork and hard paper were tried, and felt, feathers, and even hay were used for upholstering the boxes, which were often called ‘hay boxes’ or ‘hay cookers.’ p. 305

Osborne, John Ball (April 17, 1913). Market for fireless cookers in France. Daily Consular and Trade Reports, Number 89, 305-308. Bureau of Foreign and Domestic Commerce. U.S. Department of Commerce.

Of course, the "fireless" method of cooking — application of initial heat to food and then its placement within some sort of protected, insulated environment for an extended period — did not make its first appearance at the Paris Exposition of 1867.

A 1886 Smithsonian Report documented cooking methods in long use by the indigenous peoples of North America. Frank Hamilton Cushing described the Havasupai Roasting Tray and the Havasupai Boiling-Basket of Cataract Canyon, Arizona.

They [the Havasupai or Cocouinos, of Cataract Canyon, Arizona] had not yet forgotten how to boil food in water-tight basketry, by means of hot stones, and continued to roast seeds, crickets, and bits of meat in wicker-trays, coated inside with gritty clay....A round basket-tray, either loosely or closely woven, is evenly coated inside with clay, into which has been kneaded a very large proportion of sand, to prevent contraction and consequent cracking from drying. This lining of clay is pressed, while still soft, into the basket as closely as possible with the hands and then allowed to dry. The tray is thus made ready for use. The seeds or other substances to be parched are placed inside of it, together with a quantity of glowing wood-coals. The operator, quickly squatting, grasps the tray at opposite edges, and, by a rapid spiral motion up and down, succeeds in keeping the coals and seeds constantly shifting places and turning over as they dance after one another around and around the tray, meanwhile blowing or puffing the embers with every breath to keep them free from ashes and glowing at their hottest. That this clay lining should grow hard from continual heating, and in some instances separate from its matrix of osiers, is apparent. The clay form thus detached would itself be a perfect roasting- vessel.

Among the Havasupai, still surviving as a sort of bucket, is the basket-pot or boiling-basket, for use with hot stones, which form I have also found in some of the cave deposits throughout the ancient Zuñi country. These vessels...were bottle shaped and provided near the rims of their rather narrow mouths with a sort of cord or straphandle, attached to two loops or eyes...woven into the basket, to facilitate handling when the vessel was filled with hot water. p. 484-485

Cushing, F.H. (1883). A study of pueblo pottery as Illustrative of Zuñi culture-growth. Fourth Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution 1882-1883. Smithsonian Institution. Bureau of Ethnology. J.W. Powell, Director, 473-521. Available at: https://archive.org/details/annualreportofbu418821883smit.

Walter Hough added to the Smithsonian's documentation of traditional cooking methods with his description of the ways that indigenous people in California cooked with hot stones and pit ovens.

The Pomos of California made a fire and put in stones to heat. When they were hot half of them were taken out and the remainder pushed together to form a layer, and were covered with a layer of oak and iris leaves. Acorn meal was then put on this layer, then a layer of leaves, and finally the remaining hot stones. Six inches of earth was piled on top and the heap was left to cook for six or eight hours.

The type of pit oven in which the heating medium is hot rocks has been observed in many parts of the world. Even the western Eskimo cook and render harmless the roots of the wild parsnip in an underground oven with hot stones....

Cooking by absorbed heat under conditions of good insulation is effected by the fireless cooker. With the adjuncts of heated irons or stones, the resemblance to the pit oven is apparent. The preservation of heat by insulation has long been known, and the efforts to prevent loss by radiation has occupied engineers and inventors and has produced a remarkable series of devices. The classical reference in Juvenal's satires to the custom of the Jews of keeping food warm over the Sabbath in baskets of hay suggests the hay cooker, which preceded the fireless cooker. p. 36-37; 44

Hough, W. (1926). Fire as an Agent in Human Culture. Smithsonian Institution. United States National Museum. Bulletin 139. Available at: https://doi.org/10.5479/si.03629236.139.i.

A flurry of publications authored by employees of the U.S. Department of Agriculture appeared in the 1910s describing the fireless cooker and advocating its use by the homemaker. Here is a sample:

The fireless method of cooking made a significant appearance in the ranks of the American military during the early years of the twentieth century and the First World War era. These publications explained its value in caring for the troops.

When an army is in the field, camping perhaps for the night or resting on their arms in trenches, in the presence of the enemy, it is out of the question to establish elaborate cooking facilities. It is often impossible to maintain fires over which to cook the soldier's repast. Under the new system all this can be avoided by starting out in the morning with food that has been placed on or in the cooking range at some convenient place of culinary operations. When meats, vegetables and coffee, for instance, have been cooked thirty minutes over a range or in the oven, they are placed in the fireless cooker, locked in, and this receptacle, containing enough food for the company at noon or at night, is packed on the Army wagons with the tentage, and follows the troops to the bivouac. There all that will be necessary will be the opening of the cooker and the removal of the articles of food. After a period of six or seven hours the meats and vegetables and the drinkables will be found to be fully cooked and palatable; roast beef will be at a temperature of 160 degrees, a ham will be hot at a temperature of 164 degrees, the vegetables will have a temperature of 140 degrees; coffee seems to get hotter than anything else and has a temperature of 172 degrees after its period of imprisonment. In the Army tests two chickens, officially described as old and tough, were converted into something tender and appetizing by this process. p. 449-450

U.S. War Department. (1917). Manual for Army Cooks, 1916. Available at: https://archive.org/details/manualforarmycoo1917unit(link is external).

A fireless cooker is an air-tight receptacle for the slow preparation of partly cooked food by heat stored up in the food, or mechanically introduced as when soapstones are used. It is also used to preserve the temperature of food cooked or uncooked.

It is generally a box-like arrangement lined with a nonconducting material within which is the well or reservoir, into which the vessel containing the hot food is placed.

Many different makes of fireless cookers are found on the market, and various material such as asbestos, paper felt, hay, indurated fiber, etc., are used as nonconductors. In some types heated soapstones are placed in the well to keep the food at a cooking temperature for long periods, or to supply the heat ordinarily given to the food before it is placed in the cooker…. The advantages are: The food may be served warm on the march or upon arrival in camp; it saves fuel; being a slow process it renders such food as tough meats tender and palatable; and the food, having been placed in the cooker, requires no further attention. p. 123

Andrews, L.C. and Wood, L. (1916). Fundamentals of Military Service. Philadelphia: J.B. Lippincott Company. Available at: https://archive.org/details/fundamentalsmil00andrgoog(link is external).

Arrangements should be made so that when on the march men may be given their mid-day meal almost immediately after reaching camp, and the most helpful auxiliary to this is the fireless cooker. One of these can be easily made from a good-sized dry goods box, padded with hay held in place by old saddle blankets, leaving room for two large milk cans that will carry enough food and coffee for the command. The cooks will fill these with boiling hot contents after supper the night before, put them in the box, stuffing hay in about them, and close it; this box will be loaded at the rear end of the wagon, and a hot meal may be served the instant the wagon arrives in camp. Many troops in the regular service take a light spring wagon with them in the field, which carries the fireless cooker, picket line, and other small conveniences, and reaches camp ahead of the command. When the troop arrives the picket line is ready to be stretched and the lunch ready to be served. This adds tremendously to the comfort of the men and the esprit of the organization. p. 365-366

In America, [fireless cookers] were often called ‘hayboxes,’ because that’s what the old-fashioned version was: a wooden box stuffed full of hay in such a way that there was a space for the pot in the middle, and a pillow of cotton ticking, stuffed with more hay, that went over the top. A hundred years ago you could get elegant models from department stores that had porcelain-coated steel cases, rock wool insulation, and easy-to-clean metal liners with pots sized to fit; the best models had soapstone disks you could stick in the oven during the day’s baking, then drop into the fireless cooker, put a pot of soup or stew on top, and have it piping hot for dinner six hours later. p. 137

Greer, J.M. (2013). Green Wizardry: Conservation, Solar Power, Organic Gardening, and Other Hands-On Skills From the Appropriate Tech Toolkit. British Columbia, Canada: New Society Publishers.

As the fireless cooker advanced and became more sophisticated than the standard "wooden box stuffed full of hay," kitchen appliance companies such as the Chambers Manufacturing Company began to manufacture and market them to the homemaker. The models became progressively more elaborate and expensive.

Here is a sample of illustrations taken from company catalogs, advertisements, and home economics texts.

Chambers Manufacturing Company. (Undated, Late 1920s). The Chambers Fireless Gas Range. Available at: https://archive.org/stream/1927IdleHourCookbookFromDwayner/Chambers Catalog - Late 1920s#mode/

As modern stoves and electrical cooking appliances came into use, fewer and fewer cooks continued to use fireless cookers. Advertisements for commercial cookers disappeared from newspapers, and directions for using them disappeared from recipe books.

Mooney-Getoff, M. (2004). “Fireless Cookers.” The Oxford Encyclopedia of Food and Drink in America, Second edition. Volume 1. Edited by Andrew Smith. p. 762-763. Oxford University Press

In a way, the demise of the fireless cooker for everyday use in the middle-class kitchen was rooted in its very beginnings. When it first appeared in the marketplace it was oversold by many kitchen equipment manufacturers and home economists alike as the ultimate answer to every homemaker's struggle with cooking: including finding enough time, energy, planning, and expertise. Although the fireless cooker offered a real convenience — cooking food without a need for constant attention at the stove or oven — it still required quite a bit of planning, skill, and work, just like the modern slow cooker. The following commentators point out many of the limitations and problems of this particular appliance.

The term ‘Fireless Cooker’ is really a misnomer and it is very unfortunate that it has become attached to a device in which cookery is done by the process of retaining heat, once stored. The so-called Fireless Cooker as it exists today is an application of the old Norwegian cooking box, which is often referred to in our books of Physics as one of the best illustrations of the use of non-conductive material in retaining heat. The fireless cooker is not a miracle working cookery machine; and it has been handicapped from the start, not only by its misnomer, but by the extravagant claims that have been made for it by its admirers and promoters. Intelligently used it is a highly desirable addition to the kitchen equipment, but it can never entirely supersede the cooking stove, nor is it by any means the most desirable method of carrying on all cookery processes. It will always be necessary for the housewife to employ some sort of a cook stove on which to start the cooking of the food material, but the process may then be finished, if desired, in the fireless cooker.

This device, as was previously stated, is only a means for retaining heat previously applied. The chief essential of its construction, therefore, is that it shall be well insulated, that is thoroughly padded with non-conducting material so that hot things introduced into it shall remain hot, and cold things remain cold. The principle, in short, is the same as that of the Thermos bottle. p. 537

Every woman who makes it her business to keep abreast of the times with regard to household appliances knows that hardly any other modern invention has caused so much division of opinion as has the fireless cooker. Some women feel that housekeeping without it would resolve into the drudgery of our grandmothers’ days. Others declare that it is an entirely superfluous luxury, and, in the long run, is more bother than it is worth.

Both are right and both are wrong. The chief trouble with the fireless cooker is its name. The next is the energy with which it is praised by its friends and abused by its enemies. In the first place the idea is by no means new. Just as paper-bag cookery is merely the revival and development of a method long in use, so the most modern of fireless cookers is only the old Norwegian cooking box in a new dress.

Unfortunately for the general success of a most useful invention, the extravagant claims made for the fireless cooker raised expectations which could have been fulfilled only by a miracle-working machine. Misled by its name, an amazing number of women have been frankly disappointed to learn that the cooker requires any heat at all.

‘We thought it cooked without any fire,’ is the usual comment, ‘and why shouldn’t it if it is a fireless cooker?’

…Unfortunately, the cooker has been much abused by those who have considered its chief value to lie in the assumption that the ‘silent servant’ could evolve a course dinner done to a turn while their minds and interests were otherwise engaged. Such have often—and rightly—been doomed to disillusionment as well as to a very indifferent, if not absolutely, impossible meal. With a clever intelligence behind it the fireless cooker is invaluable for the uses to which it is adapted. Why should it be required to that the place of other tried and satisfactory methods?’

Nor will the presence of a cooker make it any the less necessary for the mistress or the professional cook to thoroughly understand the culinary art. They must know about meats, and cereals, and vegetables, and flavors, and their combinations and extension, to which attention has been called. It is simply, in all households, valuable because it preserves flavors, eliminates the danger of burning or overcooking, reduces the cost of fuel by three-fourths or more, makes it easier to wash the pots and in other ways saves no end of drudgery; while for those who have to do their own cooking its advantages in giving leisure for other work, or diversions while the cooking goes on, are incalculable.  p. 196

A fireless cooker is an insulated container capable of maintaining a temperature at which food can be cooked. The practical fireless cooker is helping families in Kenya to escape the vicious cycle of poverty that is perpetuated by the sheer struggle to survive.

By making families less dependent on fuel, they no longer have to make the heartbreaking choices between sending their children to school and short-term survival, or going to work and collecting wood.

The 'fireless cooker' uses stored heat to cook food over a long period of time. The food is cooked on a traditional stove, before it's transferred to the fireless cooker. The cooker is well insulated, keeping the heat in the food and allowing it to continue cooking inside.

A simple basket, insulated with local resources such as banana leaves or old clothes, can reduce fuel use by 40%, preserving scarce food and saving people hours of precious time. p. 33

Geoffery, E.O. (2016). Report on Industrial Attachment held at the Kenya Forest Service. Ngong Road Forest. Nairobi Forest Conservancy Headquarters. University of Nairobi.

The fireless cooker has been reimagined as an insulated box or basket and a free-standing fabric bag as a way for low-income families to cook hot and nutritous meals that use less fuel, are less dependent on expensive kitchen cooking equipment, and produce less indoor pollution.

These current-day, scholarly journal articles and reports describe some of the benefits derived from this cooking tool.

(Note: No endorsement of the Wonderbag fireless cooker, the Kenya Ceramic Jiko or any other commercial product mentioned in this piece should be inferred.)

The fireless cooker is a little-used but valuable technology, comprising an insulated basket into which pre-heated food is left to cook in its own heat. During the recent Practical Action smoke alleviation project, the first fireless cooker demonstration used very smart baskets and expensive foodstuffs. The women felt it was ‘too expensive’ for them. In later demonstrations the project team discussed why the ‘fireless’ cooked the food, and women made their own baskets with local materials, thus empowering them to become the technologists. It provided a way of using the trusty open fire whilst still alleviating smoke and saving fuel. These fireless cookers provided an entry point for other, more expensive, smoke alleviation technologies. Laboratories cannot answer the questions that are closest to hearts and hearths of the cooks as they do not address the user’s lifestyle. The success of the fireless cooker is based on the concept of the ‘need for insulation’ as a technology, not on affordability of a technology. Their success in low income communities is evidence that women have been able to take up the technologies, but under their own terms and conditions. p. 12

The fireless cooker is a simple insulated container (available in many designs) that uses the heat of the food being cooked to complete the cooking process. In fireless cooking, food is heated to the boiling point and then insulated. The fireless cooker normally requires up to twice as much time to cook food than the normal stovetop cooking time. This simple and local innovation has many advantages such as preventing heat from escaping into the environment; hence no additional energy is needed to complete the cooking process. The food can be left in the cooker until it is ready to serve and will keep hot for hours. Also, foods which require long cooking can be prepared in the fireless cooker. Use of the fireless cooker could save fuel to the extent of one third of the total consumption by avoiding the need for reheating, which may save between 20 to 80% of the total energy. The decrease in wood burning limits contact with smoke, and is environmentally friendly. p. 12592

A hay box (or fireless cooker/straw box/insulation cookers/retained-heat cookers) is an insulated container where a partially cooked food can be stored in order to continue cooking with no need to consume further fuel or external heat.... In such contexts with limited access to fuels, particularly for food requiring a long cooking time (i.e. legumes and rice), food can be initially brought to a boil with a traditional stove and then placed in a hay box to complete the cooking without burning any further fuel.... Therefore, instead of simmering it over fire, the food continues to cook over a longer period inside the fireless cooker, using its own stored energy and reducing the fuel use by even 40%.... As main drawbacks, the length of cooking time required in a hay box is higher compared with a traditional stove – food prepared in a hay box normally requires more than one to two times the normal cooking time..., and there is risk of bacteria growth if food remain too long at temperatures dropped below 60 °C.

They can be easily built starting from a basket, cloths and pillows, at zero or very low cost. Within humanitarian settings, The Vajra Foundation Holland...has been active in the Bhutanese refugee camps in Nepal since 1995 to bring both hay boxes and solar cookers to the refugees there. From 2001 to 2003 hundreds of hay boxes were distributed, covering the main sectors of Beldangi-I camp. After 2006, the Vajra Foundation Holland received nearly $1 million for their programme, and they disseminated 6300 solar cookers and 12,000 hay boxes to families in the camps as well as an extensive use and maintenance training. The UNHCR [The United Nations High Commissioner for Refugees] reports that a total of 3500 units of Save80 stoves and fireless cookers were distributed in 2010 in refugee camps in Chad, Djibouti, Ethiopia, Kenya, Rwanda, Sudan, Togo and Uganda. p 199-200

The Fireless Cooker in the present study was designed keeping in mind the Indian dietary pattern. It could be used suitably for cooking rice, dals, vegetables and other boiling purposes. The cooker with heat retention qualities has also an additional advantage of keeping the food within ‘safe limits’’, Longre’e (1980) suggests that the temperatures between 7° and 60° C are most favourable for microbial growth) and avoiding preheating of food at the time of serving. The fireless cooker also fulfilled the three basic selection criteria of any equipment viz. low in cost, ease in understanding the use and operation and ease in maintaining and storing the equipment. p. 99

Kaushik, V. (2010). Designing fireless cooker of indigenous insulation material for better heat retention. Journal of Human Ecology, 30(2), 99-104. Available at: https://www.tandfonline.com/doi/abs/10.1080/09709274.2010.11906278

Retention Heat Cookers (RHC), such as a WonderBag, is a promising solution to increase the cooking energy efficiency which employs the retained heat for cooking in a rural kitchen or elsewhere. All sort of food items may be cooked in WonderBags, including rice, potato, chicken, vegetables, and beef etc. which are cooked with water. When the food is heated to its boiling temperature on the cooking stove, the food can be continued to be cooked using WonderBag by retaining the heat. This option offers several benefits including reduction of fuel usage, reduction of greenhouse gas emission, energy savings for cooking leading to monetary savings, indoor air pollution reduction etc.

Sadrul Islam, A.K.M. & Salehin, S. (2014). Performance Test of Wonder Bag: A Pathway to Reduce Cooking Energy Consumption and CO2 Emission. Bangladesh: Department of Mechanical and Chemical Engineering. Islamic University of Technology (IUT). Organisation of Islamic Cooperation (OIC) Board Bazar.

WonderBag is a Wonder heat retention cooker. It saves cooking time and fuel. This study aims to assess that ‘Whether WonderBag cooking technique does have any effect on Nutrient Quality and Shelf Life Stability of food’? To address this issue, three food items- Rice, Mixed vegetables and Chicken, most common food items frequently consumed by mass people, were selected to cook with WonderBag and gas stove cooking techniques. After completion of cooking, samples were collected from each of the cook foods as per predesigned sampling time schedule and procedure. Nutrient composition was analyzed with standard and validated analytical methods. Shelf life stability was assessed by evaluation of physical characteristics, and by analysis of microbial loads at different time intervals over a period of 12 hours after cooking the foods. Cook food items were also served to the research team members, lab staff and GIZ advisor to taste its palatability and deliciousness. Statistical analysis was employed to calculate mean and standard deviation. Independent t-test was performed to observe variation (if any) of nutrient constituents in the WonderBag foods as compared to the gas cook food items. Linear regression analysis was also done to find correlation of microbial loads with time elapsed and natural temperature fall.

Finding shows [sic] that nutrient composition of WonderBag food remains same and microbial growth is extremely low. Man time use is noted to be less of around 31 to 61 percent in the WonderBag cooking technique. Further, WonderBag food is comparatively delicious.

It is evident that WonderBag cooking do [sic] retains Nutrient Quality and significantly extend Shelf Life Stability of foods. p. 2

Nazrul Islam, S., Huque, S., and Islam Khan, N. (2014). Nutrient Quality of WonderBag Cooking: Nutrient Quality and Shelf Life Stability of WonderBag Food. Bangladesh: Institute of Nutrition and Food Science. University of Dhaka.

In Kenya, about 85 per cent of households in urban areas use the improved Kenya Ceramic Jiko [KCJ] stove, which has an energy conversion efficiency of about 33–35 per cent compared to 10–15 per cent obtained in traditional stoves. Use of the Kenya Ceramic Jiko enables poor urban households to make financial savings of 26 per cent of annual household income. Another type of stove that could contribute to a reduction in the quantity of charcoal used is the fireless insulation-based cooker. A fireless cooker completes cooking that is initiated by another stove such as the KCJ. Tests have shown that this cooker despite cooking food for a long time can reduce cooking energy consumption by 50 per cent. This suggests that a combination of ceramic stove and fireless cooker can reduce household charcoal consumption by 75 per cent (Mugo et al. 2007). Fireless cookers are made from a simple basket, insulated with local resources such as banana leaves or old clothes. Use of improved stoves could reduce the negative health effects of using of charcoal, where for example respiratory infections in children and women fell by 60 per cent and 65 per cent respectively when the KCJ was used. p. 364-365

Njenga, M., Karanja, N., Munster, C., Iiyama, M., Neufeldt, H., Kithinji, J. & Jamnadass, R. (2013) Charcoal production and strategies to enhance its sustainability in Kenya. Development in Practice, 23(3), 359-371. Available at: https://doi.org/10.1080/09614524.2013.780529(link is external).

During an interview with a West Kochieng citizen who has established a relatively profitable enterprise in Upesi stove and fireless cooker sales, she indicated that awareness of the dangers of kitchen smoke altered her perception of the risks several years ago and consequently led her to adopt the Upesi stove [a ceramic stove], fireless cooker and eaves spaces in her outdoor kitchen….

‘Awareness is what has increased. Because people now are actually realising. First of all there isn't much money. Secondly there is isn't much firewood. So now is when people are realising that this thing is able to save them, because it costs less and it uses less firewood. And they have seen people around them using it, and it is now real to them that it can save cost.’ (Interview West Kochieng Citizen 1). p. 207

Sesan, T. (2012). Navigating the limitations of energy poverty: Lessons from the promotion of improved cooking technologies in Kenya. Energy Policy, 47, 202-210.

Finally, this video has no dialog or narration, but shows how food emerges from a fireless cooker hot and ready to eat after the cooking process has been completed properly. This video shows Faustine Odaba of the Natural Resources and Waste Management Alliance presenting the fireless cooker in Kampala, Uganda, 2017.

Video with captions: https://www.youtube.com/watch?v=NySEH2sXgJA&feature=emb_imp_woyt

Original video without captions is available from Bernhard Müller at: https://www.youtube.com/watch?v=UACXAsyvcR4

Emily Marsh, Ph.D., MLS