SECRETION OF THE BILE. 337 



is curdled. The altered organic matter also acts upon the olea- 

 ginous ingredients, which are partly decomposed; and the milk 

 begios to give off a rancid odor, owing to the development of 

 various volatile fatty acids, among which are butyric acid, and the 

 like. These changes are very much hastened by a moderately 

 elevated temperature, and also by a highly electric state of the 

 atmosphere. 



The production of the milk, like that of other secretions, is liable 

 to be much influenced by nervous impressions. It may be increased 

 or diminished in quantity, or vitiated in quality by sudden emo- 

 tions ; and it is even said to have been sometimes so much altered 

 in this way as to produce indigestion, diarrhoea, and convulsions in 

 the infant. 



Simon found 1 that the constitution of the milk varies from day to 

 day, owing to temporary causes ; and that it undergoes also more 

 permanent modifications, corresponding with the age of the infant. 

 He analyzed the milk of a nursing woman during a period of nearly 

 six months, commencing with the second day after delivery, and 

 repeating his examinations at intervals of eight or ten days. It 

 appears, from these observations, that the casein is at first in small 

 quantity ; but that it increases during the first two months, and 

 then attains a nearly uniform standard. The saline matters also 

 increase in a nearly similar manner. The sugar, on the contrary, 

 diminishes during the same period ; so that it is less abundant in 

 the third, fourth, fifth and sixth months, than it is in the first and 

 second. These changes are undoubtedly connected with the in- 

 creasing development of the infant, which requires a corresponding 

 alteration in the character of the food supplied to it. Finally, the 

 quantity of butter in the milk varies so much from day to day, 

 owing to incidental causes, that it cannot be said to follow any 

 regular course of increase or diminution. 



6. SECRETION OF THE BILE. The anatomical peculiarities in the 

 structure of the liver are such as to distinguish it in a marked 

 degree from the other glandular organs. Its first peculiarity is 

 that it is furnished principally with venous blood. For, although 

 it receives its blood from the hepatic artery as well as from the 

 portal vein, the quantity of arterial blood with which it is supplied 

 is extremely small in comparison with that which it receives from 



1 Op. cit., p. 337. 

 22 



