304 SECRETION 



tenth day, but they are rare. After the fifteenth day, the milk does 

 not sensibly change in microscopical or chemical characters. 



LACTEAL SECRETION IN THE NEWLY-BORN 



In infants of both sexes there usually is a certain quantity of secre- 

 tion from the mammary glands, beginning at birth or two or three days 

 after and continuing sometimes for two or three weeks. The quantity 

 of liquid that may be pressed out at the nipples at this time is variable. 

 Sometimes only a few drops can be obtained, but occasionally it amounts 

 to one or two drachms (3.7 or 7.4 grams). Although it is impossible to 

 indicate the object of this secretion, which takes place when the glands 

 are in a rudimentary condition, it has been so often observed and de- 

 scribed by physiologists, that there can be no doubt in regard to the 

 nature of the liquid and the fact that the secretion is almost always 

 produced in greater or less quantity. 



COMPOSITION OF THE MILK OF THE INFANT (GUBLER) 



Water . . . . . . . . ,\ . v,. V , i. 894.00 



Casein . '; ' 7<J ..." - ." "- . 26.40 



Sugar of milk . .'.'. ..' .; . 62.20 



Butter . ' : . ' .' -'.'. '. . . . ' .' . . . ' . 14.00 



Earthy phosphates . . . . ... .V -. '. , 1.20 



Soluble salts (with a small quantity of insoluble phosphates) . . 2.20 



IOOO.OO 



This secretion does not differ much in its composition from ordinary 

 milk. The proportion of butter is less, but the proportion of sugar is 

 greater and the quantity of casein is nearly the same. 



Of the other liquids classed as secretions, the saliva, gastric juice, 

 pancreatic juice and the intestinal secretions have already been described 

 in connection with the physiology of digestion. The physiology of the 

 lachrymal secretion will be taken up in connection with the eye, and the 

 bile will be treated of fully under the head of excretion. 



