LACTATION 615 



not necessarily even a female function ; but such cases are at all events 

 exceedingly rare. 1 Knott mentions cases in which suckling occurred 

 in a bull, a male goat, a wether, and in men. He also cites instances 

 of virgin girls who were nurses secreting copious supplies of milk as 

 a consequence of allowing infants to suck their nipples; and thus he 

 supports Heape's objection to the fetal hormone theory. Gellhorn 2 

 cites similar cases, including one o'f a virgin monkey (Cercopithecus). 

 Another case is mentioned of a woman who suckled children 

 uninterruptedly for forty- seven years, and in her eighty-first year 

 had a moderate but regular supply of milk, 3 thus showing that 

 mammary secretion may continue exceptionally for long after the 

 menopause, and presumably, therefore, in the absence of any sort of 

 stimulus from the generative organs. This observation further 

 supports the idea referred to above, that normal suckling acts by 

 itself as a physiological stimulus for mammary secretion. 



Halban 4 has remarked that the seat of the stimulus for milk 

 secretion nrnst be placed outside the foetus, since parturition may 

 result not only in the mother secreting but also the foetus which 

 produces the so-called "witch's milk." Again, cases are described 

 in which a woman has produced a healthy, well developed child, and 

 yet secreted very little milk. 5 O'Donoghue has pointed out that 

 the rabbit secretes milk several days before parturition, whereas 

 man and Dasyurus do not do so until several hours after it. More- 

 over, Hammond 7 has recorded a case of a goat which secreted large 

 amounts of milk (800 c.c. daily) for three weeks before parturition. 



An equally forcible objection to the theory of the fo3tal hormone 

 is supplied by the Monotremata, which are the lowest order of 

 Mammalia. These animals are oviparous, the developing embryo 

 being contained in an egg, which does not enter into any sort of 

 connection with the uterine wall. Halban, 8 however, has made the 

 suggestion, which is quoted by Miss Lane-Claypon and Starling, that 

 since the embryo goes on increasing in size during its passage down 

 the female generative tract, and since the shell of the egg is porous, 



1 The occasional occurrence of milk secretion in the newly born, both males 

 and females, is well known. 



2 Gellhorn, loc. cit. 



3 Knott, loc. cit. 



4 Halban, "Die innere Sekretion von Ovarium und Placenta," Arch. f. Gyn., 

 vol. Ixxv., 1905. 



5 Hammond, "On the Causes Eesponsible for the Developmental Progress 

 of the Mammary Glands in the Rabbit during the latter part of Pregnancy," 

 Proc. Roy. Soc., B., vol. Ixxxix., 1917. 



6 O'Donoghue, "The Growth Changes in the Mammary Apparatus of 

 Dasyurus and the relation of the Corpora Lutea thereto," (Juar. Jour. Micr. 

 Science, vol. Ivii., 1911. 



7 Hammond, loc. cit. 



8 Halban, loc. cit. 



