152 COMPENSATORY PROCESSES 



planation of the fact. Voit, in effect, says that work is "clone- 

 as in many machines, by a store of force laid up at some other 

 time, as by winding up a spring for example, this store being 

 laid up by the intermediation of albumen binding the oxygen 

 and then splitting up ; but he does not make it clear how this 

 takes place without increase of the urea according to the work, 

 for the more work a machine does the more winding up it 

 needs, no matter when. Voit, besides, shows that fat and milk 

 are formed from albuminous matters and not from the non- 

 nitrogenous principles, and he rather falls back into the old ther- 

 mogene theory, for he says : " In a pure albuminous diet the fat 

 produced from it serves for heat production, while by introduc- 

 tion of easily combustible carbo-hydrates into the diet, these 

 last are oxidated and the fat originating from the albumen 

 remains accumulated" (p. 81). Voit resembles Goodsir and 

 Beale in describing " milk as a dissolved organ of the body, and 

 not a simple nitration from the blood " (p. 83), and that in the 

 secretion the mammary gland uses albuminous material for the 

 building up of cells, which then partly undergo fatty degenera- 

 tion and partly take up fat from the blood. In respect to the 

 difficulty of the non-increase of urea in proportion to work, the 

 explanation of Kiihne is probably the one with which we must 

 be satisfied for the present, viz., that compensatory pro- 

 cesses are taking place at the same time, of the exact nature and 

 amount of which we are at present ignorant, but which may 

 " decompose an absolutely great amount of albumen while pro- 

 portionately little is oxidated down to urea, and therefore the 

 excretion of the latter is as slightly increased during work as 

 experiment shows."* 



A single yeast cell will convert sixty times its weight of 

 sugar into carbonic acid and the still combustible alcohol with 

 evolution of active force as heat, not by catalysis, for there are 

 other products, and the cell either grows or wastes away accord- 

 ing as it is furnished with a due amount of nitrogenous pabu- 

 lum. In this case some compensatory processes must have 

 been at work, and the same particles of nitrogen must have 

 taken part in the vital decomposition and recomposition over 

 * " Physiologische Chenne," p. 327. 



