332 PHYSIOLOGICAL CHEMISTRY 



such distinctness. The principle, however, is always to be observed. 

 The food of those belonging to the well-to-do classes, i. e.,of those who 

 do no hard physical work, in all countries contains the most meat. 

 This, however, is no luxury, but is based upon physiological grounds. 

 Comparing different countries, or different classes in the same country, 

 we always obtain the following result. To the degree that pure hand 

 labor is replaced by the work of the head, and that of overseeing 

 machines, to that same degree is the consumption of meat increased. 

 This is shown most obviously, however, by the comparison of the 

 country population with that of the city. The modern mill-hand lives, 

 it is true, by the work of his hands, but that work is quite different 

 from that done by the farm laborer. The overseeing and directing of 

 the complicated machines, as every other form of skilled labor, re- 

 quires attention, intelligence and dexterity, but does not require the 

 muscular exertion necessary for mowing, threshing, and the felling of 

 trees. With the difference in activity there must also be a difference 

 in the quantity and kind of food. The people in a city in general eat 

 less in total amount, but this food is qualitatively different, i. e., 

 must consist of substances relatively rich in proteids, as meat and 

 other animal products. 



From the politico-economical, as well as from the medical, point of 

 view the smaller amount of food consumed by the mill-hand, as com- 

 pared to that of the farm laborer, is regarded as a sign of degeneration. 

 This is obviously untrue, for there is no general standard of nutrition 

 which is applicable, or even desirable, for all men. The nutriment, 

 with respect to quantity, is dependent solely upon the amount of 

 muscular work done. On the other hand, the increased consumption 

 of meat, eggs, and other foods, agreeable to the taste because rich in 

 proteids, has been attributed to the greediness of the urban popula- 

 tion. Nothing could be more false. It is just for this large class that 

 the enjoyment of meat and other foods rich in proteids is a physio- 

 logical postulate; and for the other large class making up the urban 

 population, merchants, officials, clerks, etc., this is true in even a 

 more striking degree, for the physical work necessary in such occu- 

 pations is still smaller in amount, and their food must consequently 

 be even richer in proteids. 



It is not for me to draw further conclusions from the physio- 

 logical principle that the food of the urban population should contain 

 less vegetable and more animal substance. I must rather consider 

 the influence of these relations upon physiology itself. The classes not 

 doing severe physical work are the higher and better-to-do, and, since 

 they are great meat-eaters, it is but too easy to conclude that in gen- 

 eral meat-eaters are the most valuable and best. This opinion is very 

 rife in lay circles, and even physiology has not long been free from it. 

 The great Liebig, the founder of the doctrine of scientific nutrition, 



