484 NUTRITION. 



Per cent. 



Adipose tissue 97.0 



Spleen 63.1 



Liver 56.6 



Muscles 30.2 



Blood 17.6 



Brain and spinal cord . . 0.0 



Thus, the loss during starvation fell most heavily on the fat, indeed nearly 

 the whole of this disappeared. Next to the fat, the glandular organs, the 

 tissues which we have seen to be eminently metabolic, suffered most. Then 

 come the muscles, that is to say, the skeletal muscles, for the loss in the 

 heart was very trifling ; obviously this organ, on account of its importance 

 in carrying on the work of the economy, was spared as much as possible ; it 

 was, in fact, fed on the rest of the body. The same remark applies to the 

 brain and spinal cord; in order that life might be prolonged as much as pos- 

 sible, these important organs were nourished by material drawn from less 

 noble organs and tissues. The blood suffered proportionately to the general 

 body-waste, becoming gradually less in bulk, but retaining the same specific 

 gravity ; of the total dry proteid constituents of the body, 17.3 per cent, was 

 lost, which agrees very closely with the 17.6 per cent, dry material (almost 

 wholly proteid) lost by the blood. It is worthy of remark that the tissues 

 in general become more watery than in health. Similar observations on 

 other animals have led to similar results, the chief discordance being that 

 in some cases the bones have suffered considerable loss, in others compara- 

 tively little. We might be inclined to infer from these data the conclu- 

 sions that metabolism is most active in the adipose tissue, next in such 

 metabolic tissues as the hepatic cells and spleen-pulp, then in the muscles, 

 and so on ; but we have no warrant for these conclusions. Because the 

 Joss of cardiac and nervous tissue was so small, we must not therefore, 

 infer that their metabolism was feeble ; they may have undergone rapid 

 metabolism, and yet have been preserved from loss of substance by 

 their drawing upon other tissues for their material. The great loss of 

 adipose tissue is obviously to be explained by the fact that that tissue 

 is essentially a storehouse of material, and the similarly great, though less, 

 loss in the spleen and liver indicates, as, indeed, the facts recorded in the 

 previous chapter suggest, that these organs, too, serve in part as store- 

 houses. 



During the starvation period, the urine contained, in the form of urea 

 (and that practically represents all the nitrogen of the urine), 27.7 grammes 

 of nitrogen. Now, the amount of muscle which was lost during the period 

 contained about 15.2 of nitrogen. Thus, more than half the nitrogen of 

 the output during the starvation period must have come ultimately from the 

 metabolism of muscular tissue. This fact we have already used in discus- 

 sing the history of urea, and shall have occasion to make further use of it 

 hereafter. The amount of urea excreted per diem has been observed, in 

 some cases, to fall very rapidly during the first day or two of starvation, 

 and then to diminish gradually, though often showing considerable irregu- 

 larities. In other cases no such large initial fall has been observed. It is 

 most marked in animals which have been well fed before the beginning of 

 the starvation, especially in those which have had a rich nitrogenous diet ; 

 and the discharge, in these cases, of an extra quantity of urea in the first 

 day or two is obviously connected with that immediate effect of food on 

 the excretion of urea, to which we have already ( 401) referred, and to 

 which we shall have to return in speaking of what is known as " luxus- 

 consumption." 



