ATAVISM. 175 
By far the most remarkable situation in which milk- 
glands arise, is in the interior of some peculiar skin-con- 
taining tumours of the ovary. I have traced every stage 
from a sebaceous gland to a nippled mamma, furnishing 
milk, in such tumours—a situation in which it would 
puzzle even Paley to imagine a useful purpose. 
These facts indicate clearly enough that a mamma 
may make its appearance in any situation of the body 
if the favouring conditions exist—z.e., a cutaneous 
recess abundantly supplied with sebaceous glands, and 
preferably on the ventral or protected aspect of the 
body ; warmth and moisture appearing to favour their 
development. 
The careful consideration of such cases clearly shows 
that to attribute such aberrant mammeze to atavism 
is inconsistent with sound reasoning: it is, however, 
obviously erroneous to regard all forms of supernumerary 
mamme and nipples as “sports,” but I am firmly of 
opinion that only those occurring in the line of the 
deep epigastric arteries, excepting those clearly due to 
dichotomy, can be with any justness considered as re- 
versionary. In the section on tumours we shall have to 
return to this subject, especially in reference to cancer, 
