LACTOSURIA IN INFANTS 285 



tion, in which there could be no occasion for colostrum pro- 

 duction normally, that the system was distinctly disposed 

 toward elimination of milk-suger in that, after administra- 

 tion of large doses of dextrose, there did not occur a glycosu- 

 ria but a lactosuria. Here the less readily assimilated carbo- 

 hydrate was forced out of metabolism by the more easily 

 consumed one. C. v. Noorden interpreted this as a provi- 

 sion in the interest of the offspring by which the economy 

 in preparation for lactation loses its power of destroying 

 milk-sugar. 44 That the lactose appearing in the urine of 

 nursing individuals has its origin from the mammary glands 

 appears from observations of disappearance of the lactose 

 from the urine of lactating guinea pigs if their mammary 

 glands are amputated. On the other hand, however, ob- 

 servations of P. Best and Porcher 45 are recorded showing 

 that removal of the mammary glands gives rise to glyco- 

 suria (not lactosuria) in lactating goats. This observation 

 (not uncontradicted) 46 was supposed to indicate that the 

 liver is thus interrupted in furnishing to the functionating 

 mammary glands the large amounts of glucose which may 

 be supposed to be converted in the latter into milk-sugar. 

 If this glucose from the liver is transferred into the circula- 

 tion without the chance of its proper use because of the 

 absence of the mammary glands, of course its excretion into 

 the urine takes place to prevent the impending hypergly- 

 csemia. 



Lactosuria in Infants. The lactosuria of infants at the 

 breast is quite a different affair. It has been carefully 

 studied by Langstein and Steinitz, 47 and is referred to a 

 pathological insufficiency of enzymic milk-sugar cleavage in 



44 Cf. C. Neuberg, 1. c., p. 240. 



45 C. Porcher, Compt. Rend., 140, 1279, 1905; 141, 73, 1905; Arch. Internat. 

 de Physiol., 8, 356, 1909; Biochem. Zeitschr., 23, 370, 1910. 



46 C. Fo& (Turin), Arch, di fisiol., 8, cited in Biochem. Centralbl., 8, 

 1587, 1909; A. Magnus-Levy and L. Zuntz, Handb. d. Biochem., 4', 382, 1909; 

 B. Moore and W. H. Parker (Yale Med. School, New Haven), Amer. Jour, of 

 Physiol., 4, 239, 1900. 



47 L. Langstein and F. Steinitz, Hofmeister's Beitr., 7, 575, 1906. 



