778 DEVELOPMENT OF THE ALIMENTARY CANAL 



early as between the fifth and sixth months. We have found distinct 

 traces of bile in the small intestine at birth, but it is even then in ex- 

 tremely small quantity, and is sometimes altogether absent. 



The meconium, therefore, and the intestinal contents generally, are 

 not composed principally, or even to any measurable extent, of the 

 secretions of the liver. They appear rather to be derived from the 

 mucous membrane of the intestine. Even their yellowish and greenish 

 color does not depend on the presence of bile, since the yellow color 

 first shows itself about the middle of the small intestine, and not at its 

 upper extremity. The material which afterward accumulates appears 

 to extend from this point upward and downward, gradually filling the 

 intestine, and becoming, in the ileum and large intestine, darker colored 

 and more pasty as gestation advances. 



It is, perhaps, of some importance in this connection, that the amni- 

 otic fluid, during the latter half of foetal life, finds its way, in greater or 

 less abundance, into the stomach, and through that into the intestinal 

 canal. Small cheesy-looking masses are sometimes to be found at birth 

 in the fluid contained in the stomach, which are seen on microscopic 

 examination to be portions of the vernix caseosa exfoliated from the 

 skin into the amniotic cavity, and afterward introduced through the 

 oesophagus into the stomach. According to Kolliker, the downy hairs 

 of the foetus, exfoliated from the skin, are often swallowed in the same 

 way, and may be found in the meconium. 



The gastric juice is not secreted before birth ; the contents of the 

 stomach being generally in small quantity, clear, nearly colorless, and 

 neutral or alkaline in reaction. 



Liver. The liver is developed at a very early period. Its size in 

 proportion to that of the entire body is much greater in the early 

 months than at birth or in the adult condition. In the foetal pig we 

 have found, the relative size of the liver greatest within the first month, 

 when it amofliits to nearly 12 per cent of the entire weight of the body. 

 Afterward it grows less rapidly than other parts, and its relative 

 weight diminishes successively to 10 per cent, and 6 per cent.; being 

 reduced before birth to 3 or 4 per cent. In man, also, the weight of 

 the liver at birth is between 3 and 4 per cent, of that of the entire 

 body. 



The glycogenic function of the liver commences during foetal life, 

 and at birth the tissue of the organ is abundantly saccharine. In the 

 early periods of gestation, however, sugar is produced in the foetus from 

 other sources than the liver. In very young foetuses of the pig, both 

 the allantoic and amniotic fluids are saccharine a considerable time 

 before glucose makes its appearance in the liver. Even the urine, in 

 half-grown foetal pigs, contains an appreciable quantity of sugar, and 

 the young animal is normally, at this period, in a diabetic condition. 

 The glucose disappears before birth, as shown by Bernard, 1 from both 



1 LeQons de Physiologie ExpSrimentale. Paris, 1855, p. 398. 



