826 STARVATION. [BOOK n. 



This fact we have already used in discussing the history of urea 

 and shall have occasion to make further use of it hereafter. In 

 some of the observations the daily output of nitrogen was found 

 to be very much greater on the first day or the first two days 

 than it became afterwards ; compared with the daily output of 

 a fed animal, the output sank rapidly on the second or third day, 

 falling much more slowly and gradually in the subsequent days. 

 In other observations on the other hand no such strong contrast 

 as regards the output of nitrogen between the initial and the 

 later days of the starvation period was met with. It would appear 

 that the occurrence of the contrast is dependent on the animal 

 having previously been fed on a large proteid diet. The large 

 discharge of nitrogen on the initial days of such cases is com- 

 parable with the increase of the discharge of nitrogen which 

 immediately follows a proteid meal ( 487), and like that indi- 

 cates that a certain portion of the proteid taken into the body as 

 food undergoes a more rapid metabolism than the rest. 



The amount of carbonic acid given out and oxygen taken in by 

 the lungs is of course diminished. In the case of a man fasting 

 for 24 hours the carbonic acid expired was found to be 168'5 cm. 

 per minute (or 2*98 cm. per kilo of body-weight per minute), and 

 the oxygen consumed 220 cm. (3'89 cm. per kilo per min.), giving 

 a total for the 24 hours of 477 grammes carbonic acid and 453 

 grammes oxygen. 



An examination of the faeces during starvation shews that the 

 bile and other secretions continue to be poured into the alimentary 

 canal, while the presence of phenol and of indigo compounds in 

 the urine shews that micro-organisms continue to work among the 

 intestinal contents. The amount of phosphorus present as phos- 

 phates in the excreta has been found to be in excess of that which 

 could be supplied by the proteids required to provide the nitrogen 

 excreted at the same time ; this, taken together with the amount 

 of lime and magnesia excreted suggests that the solid matter of 

 the bones is in such cases drawn upon. The amount of chlorides 

 secreted also seems considerable. 



Comparison of Income and Output of Material. 



521. Method. We have now to inquire how the elements of 

 food are distributed in the excreta, in order that, from the manner 

 of the distribution, we may infer the nature of the intermediate 

 stages which take place within the body. By comparing the 

 ingesta with the excreta, we shall learn what elements have been 

 retained in the body, and what elements appear in the excreta 

 which were not present in the food ; from these we may infer the 

 changes which the body has undergone through the influence of 

 the food. 



