18 THE STRUCTURE OF MAN 



soon after birth and at the time of puberty, may produce milk 

 (so-called " witch's milk ") from more or less swollen breasts. 1 

 Milk has also certainly been obtained from male goats and from 

 castrated rams, and this has been found on chemical analysis to 

 be even richer in caseine than ordinary milk. 



[In this connection it is interesting to note that Dobson has 

 called attention (British Museum Catalogue of the Chiroptera, 

 Lond., 1878, pp. 79 and 83) to the great development of the 

 teats in the males of certain frugivorous Bats. He points out 

 that while many Bats are known to bring forth two young at a 

 birth, he has never found a mother with more than one clinging 

 to her body ; and he inclines to the belief that in such cases the 

 male may relieve the female of the charge of one of the young 

 ones (as the weight of two might render flight difficult or 

 impossible). He suggests that " instances of the male performing 

 the office of nurse are probably not uncommon among Bats."] 



The following results on the subject of supernumerary breasts 

 and teats were obtained by Leichtenstern, from the study of 

 extensive data : 



Cases of polythely, with or without polymasty, were observed 

 with almost equal frequency in the two sexes. On an average, 

 one case may be expected in every 500 individuals. 



In 9 1 per cent the accessory glands and teats were developed 

 on the anterior side of the thorax, and in by far the greater 

 number (94 per cent of these) they were found below (caudad of) 

 the normal teats, in a convergent disposition. 



The following is a table showing the position occupied by 

 the accessory mammillae in the 105 cases recorded by Leichten- 

 stern : 



On the anterior side of the thorax . . 96 cases 



In the axilla . . . . 5 



On the back . . . 2 



Above the acromion . . . . 1 case 



On the outer side of the hip . . * 1 



Eudimentary breasts occurring above (cephalad of) the normal 

 ones are of rare occurrence (3 per cent), and these (Fig. 13, m") 

 always lie outside the normal mammary line in the direction 

 of the axilla. Want of symmetry, especially on the left side, is 

 common in all cases of rudimentary teats or mammary areas, in 

 whatever part of the body they occur. The rarest condition 



1 Decided swelling of the breasts is sometimes found in youths of from twenty to 

 twenty-one years of age, in cases of retarded puberty (Ammon). 



