90 EVOL UT10N AND NA TURAL THEOL OG1. 



sexes among some tribes of Polynesian islanders,* 

 many instances are on record of mammas having 

 become fully developed, and functionally active, 

 in the healthy and adult male, both in man, and 

 other animals. It is worthy of remark, that in 

 several of these cases, the organ on one side 

 only has become developed, probably owing to 

 some disease or defect on the corresponding side ; 

 and that lactation in the male, when it occurs at 

 all. is generally permanent, because it is un- 

 checked by the constitutional changes which 

 take place in the female, f 



A converse case to that of the above-mentioned 

 Polynesians, is found among a dwarf race in 

 Madagascar, in which the mammas are seldom 

 or never developed, even in the female.J Very 

 possibly both their dwarfish stature and the 

 non-development of mammas may be due to one 

 primary cause, perhaps to the whole tribe having 

 formerly been exposed to very severe privations 

 for many generations. But I do not remember 



* JBrenchley's " Cruise of the Curagoa" p. 218 



t The flow of milk is said to be rendered permanent in a milch cow 

 by spaying, though the normal effect of such an operation on an 

 animal at another time would be to produce non-development, or 

 atrophy of the mammse. 



J Petermann's " Geogr. Mittheilungen," 1871, pp. 142, 143. 



