EXCHANGE OF MATERIAL. 465 



The greatest absolute deposition of flesh in the body was 

 obtained in these cases with only 500 grms. flesh and 250 grms. fat, 

 and even after 32 days the nitrogenous equilibrium had not occurred. 

 On feeding with 1800 grms. meat and 250 grms. fat the nitrogenous 

 equilibrium occurred after 7 days ; and though the deposition of 

 flesh per day was greater, still the absolute deposit was not one half 

 as great as in the former case. Inasmuch as the quantity of pro- 

 teids does not decrease below a certain amount, it seems that the 

 most abundant and most lasting deposition of flesh is obtained with 

 a food which does not contain too much proteids in proportion to 

 the fat. The same is also true of a diet consisting of proteids and 

 carbohydrates. 



From the above conditions concerning a deposit of fat in the 

 body it follows that such a deposit may indeed occur with an 

 exclusively flesh diet, but that in this case it is only very small even 

 when large amounts of proteids are taken. For the production of 

 an abundant deposit of fat the body must take with the food, besides 

 proteids, either fats or carbohydrates or, which is best for human 

 beings, fat and carbohydrates simultaneously. The carbohydrates 

 are of special importance because they are generally cheaper in 

 comparison with the fats. As the non-nitrogenized bodies are, 

 according to all appearances, the most important source of muscular 

 activity, then diminished bodily work or rest must be a favorable 

 condition for the deposition of fat in the body. Best, with a 

 proper combination of the three chief groups of organic food, is 

 therefore of great importance in fattening, the object being to 

 cause as great an increase as possible in the mass of the proteids 

 and fats in the body in the cheapest way. 



Action of certain other Bodies on the Exchange of Material. 

 Water. If a quantity in excess of that which is necessary is intro- 

 duced into the organism, the excess is quickly and principally 

 eliminated with the urine.. This increased elimination of urine 

 causes in fasting animals (VoiT, FORSTER), but not to any mention- 

 able degree in animals taking food (SEEGEN*, MUNK, MAYER), an 

 increased elimination of urea. The reason for this increased elimi- 

 nation is sought for in the fact that the abundant drinking of water 

 causes a complete washing out of the urea from the tissues. An- 

 other view, which is defended by VOIT, is that because of the more 



