The first series of experiments was made in 1891 by the late Immanuel Munk of Berlin, privat docent of physiology at the University, followed by further experiments in 1893.[68] Four dogs in all were studied. The diet made use of was “fleischmehl” (dried meat ground to a powder), fat (suet), and rice boiled together with water. We may refer briefly to the details of one experiment. The dog weighed 10.4 kilograms, and at first was given a daily diet composed of 85 grams of rice, 29 grams of fat, and 30 grams of the flesh meal. This ration contained 30.3 grams of proteid, 31 grams of fat, and 66 grams of carbohydrate, with a total fuel value of 663 calories, or 63 calories per kilogram of body-weight. On this diet, there was at the outset a slight loss of body-weight, after which both body equilibrium and nitrogen equilibrium were practically maintained. After this preliminary period of three weeks, the day’s diet was altered by replacing 15 grams of the proteid by 15 grams of rice, so that the daily ration consisted of 15.3 grams of proteid (with 2.42 grams of nitrogen), 31 grams of fat, and 81 grams of carbohydrate, with essentially the same fuel value per kilo of body-weight as before. Later, the fuel value of the food was further increased by raising the amount of rice to 125 grams per day, the day’s ration then consisting of 15.5 grams of proteid, 37 grams of fat, and 96 grams of carbohydrate, with a total fuel value of 780 physiological heat units, or 78 calories per kilo. On this diet, nitrogen equilibrium was maintained and the animal gained somewhat in body-weight. By the seventh week, however, Munk reports that the animal began to show signs of change; there was loss of appetite, absorption of the daily food was impaired, both proteid and fat failing in large degree to be utilized, while nitrogen equilibrium could no longer be maintained. This condition continued during the next week, aggravated by vomiting and accompanied by loss of strength and vigor. At the beginning of the tenth week of this low proteid ration, the animal was in a very poor condition, with complete loss of appetite, little inclination to take food, etc. On feeding a liberal diet of fresh meat, as much as 250 grams per day, with some fat (50 grams a day), the animal speedily recovered its appetite, and in a short time was in normal condition, absorption of food and utilization of the same being as complete as at the beginning of the experiment. [68] Ueber die Folgen einer ausreichenden, aber eiweissarmen Nahrung. Ein Beitrag zur Lehre vom Eiweissbedarf. Virchow’s Archiv für pathologische Anatomie und Physiologie, Band 132, p. 91.