REPRODUCTION 877 



(Halliburton), a large amount of water, and some inorganic salts, are 

 the most important of its remaining constituents. 



Pregnancy is accompanied with vascular dilatation and hyper- 

 trophy of the mammary glands, but the mechanism by which these 

 changes are produced is unknown. Precisely similar phenomena 

 are occasionally seen in animals which have not been impregnated 

 and even in men. Humboldt relates the case of an Indian father, 

 who so well understood the responsibilities of paternity, and was so 

 capable of fulfilling them, that he suckled his child for five months 

 on the death of the mother. 



