LACTATION 571 



subject of some controversy. Bert ^ supposed that it was formed 

 from glucose which was absorbed by the cells of the mammary 

 gland from the circulating blood. The glucose, according to 

 this view, was manufactured in the liver, or, at any rate, elsewhere 

 than in the mammary gland. Bert based his hypothesis upon 

 two experiments in which the glands were removed from goats 

 which afterwards became pregnant. The urine of each animal 

 was tested during pregnancy to see if any reducing agent was 

 present, but no such substance could be found prior to the 

 birth of the kid. On the other hand, for several days after 

 parturition a substance which reduced cupric sulphate was dis- 

 covered in each case. Bert concluded that this was glucose. 

 He supposed further that the reducing body present in the 

 urine of the two goats represented glucose which in normal 

 animals would have been converted into lactose in the mammary 

 glands. The experiments were afterwards repeated by Moore 

 and Parker,^ who operated hkewise upon two goats, and obtained 

 results which were the direct opposite of those of Bert. These 

 authors consequently concluded that the complete process of 

 lactose formation takes place in the cells of the mammary glands. 



The question was subsequently reopened by Porcher,^ who 

 also repeated Bert's original experiment on a goat. After par- 

 turition in the operated animal, an intense glycosuria is said 

 to have occurred, the phenylhydrazane test showing that the 

 substance present in the urine was glucose, and not lactose or 

 some other reducing body. Porcher also removed the mammary 

 glands from four goats and one cow during lactation, and for a 

 few hours after the operation obtained marked glycosuria. As 

 a result of those experiments, taken in conjunction with those 

 of Bert, he concluded that the truth of the latter 's theory was 

 established beyond all doubt. 



More recently the writer, working in conjunction with Dr. 



^ Bert, " Sur I'Origine du Sucre du Lait," C. R. de I'Acad. des Sciences, 

 vol. Ixxxviii., 1884. 



^ Moore and Parker, " A Study of the Effects of Complete Removal of 

 the Mammary Glands in Relationship to Lactose Formation," Amer. Jour. 

 ofPhys., vol. iv., 1900. 



' Porcher, "Sur I'Origine du Lactose," C. R. de I'Acad. des Sciences, 

 vol. oxxxviii., 1904. "De la Lactosurie," Monographiea Cliniquea, Paris, 

 1906. 



