MAMMARY GLANDS. 
Although the usual number of mamme in 
human species is only two, still there 
are exceptions and instances on record of 
more having been developed. One of the 
best authenticated and most recent of these 
cases is related by Dr. Lee, in the Transac- 
tions of the Medical and Chirurgical Society 
for 1837.* 
In this instance “ the inferior or pectoral 
mamme were fully developed and in the na- 
tural situation, and their nipples, areole, and 
glands presented nothing unusual in their ap- 
pearance. Near the anterior margin of the 
axilla, a little higher up on each side, was si- 
tuated another mamma, about one-sixth of the 
size of the others. The nipples of these were 
small and flat, but when gently pressed, a 
milky fluid which had all the external cha- 
racters of the milk secreted by the other breasts, 
flowed copiously and readily from several ducts 
which opened on their extremities. When 
milk was drawn from the lower breasts, a small 
< preiel usually escaped from the nipples of 
e superior breasts, and when the draught 
came into the former, the latter invariably be- 
came hard and distended.” The flatness of 
the nipples prevented her suckling her children 
by them. Dr. Lee, inthe above paper, quotes 
five other cases from foreign authors of qua- 
druple mamme, also stating that “ in some 
women only one breast has been developed ; 
others have had two nipples placed on one 
mamma; and a few individuals have had three 
breasts, two in the natural situation and a third 
situated in the middle of the two others. Only 
one case has been recorded of five mamme in 
the human subject.” + 
Comparative anatomy.—In considering this 
division of our subject we shall especially di- 
rect our attention to those points in the anatomy 
of the mammz of animals which possess a phy- 
siological interest, omitting minute anatomical 
details unless they bear upon general principles. 
These organs in the Kangaroo, one of the Mar- 
supiata, as we have already hinted at, are 
peculiarly formed, for the young of these ani- 
_ mals, when first removed from the uterine cavity 
of its parent, is more like an earth-worm in its 
appearance than the active animal by which 
it is produced. So helpless is the condition of 
_ this young animal that it has not been inap- 
propriately called a mammary fetus, for the 
_ Mamme, in this instance, act at first like a true 
_ placenta as a permanent conductor of nutri- 
ment, and not, as in the higher Mammalia, 
a mere storehouse to be resorted to occasionally. 
Indeed, so close is the union between the pa- 
rent and its offspring, and so imperfect the 
power of the foetus to abstract nourishment by 
suction, that Geoffroy St. Hilaire had recourse 
_ to the hypothesis that there was some vascular 
connexion. But the imperfect power of the 
feetus is compensated by the addition to the 
breast of a muscular apparatus, which propels 
forwards the nutritious juices of the mother 
into the alimentary cavity of the helpless 
* Page 266. 
¥ Dict. des Sciences Méd. tom. xxxiv. p. 529. 
251 
young one. From the interesting account 
which Mr. Morgan has given of these glands* 
in the Kangaroo, we shall extratt the following 
particulars. 
In this animal there are four teats, two of 
which, in the virgin state, are at the bottom of 
a narrow pouch in which they lie hid. It is to 
one of these teats that the marsupial fcetus is 
attached immediately after its removal from the 
uterus, and their size, at first small in accord- 
ance with the minute mouth of the animal, in- 
creases with its growth. The muscular appa- 
ratus above alluded to embraces both the teat 
and the gland, and acts from the marsupial as 
its fixed point. The teat is further provided 
with a true vascular erectile tissue. 
The upper or smaller gland is perfectly 
similar in its organization to the larger, and, 
notwithstanding the doubts which Mr. Morgan 
expresses regarding its use, Mr. Owen observed 
in the instance which he has so carefully re- 
corded in the Philosophical Transactions for 
1834, that the fwetus was attached to the upper 
and not the lower nipples, and “ that the 
nipple in use by the young one of the previous 
year was the right superior or anterior one.” 
With regard to their minute structure it would 
appear from the figures of Mr. Morgan that the 
lacteal tubes originate in plexuses and not in 
cells, but the text is not very precise on this 
point. 
The consideration of the existence of these 
organs in those bird-like Mammalia, the Orni- 
thorhynchi, or duck-billed moles of Australia, 
is interesting. For the beak-bearing mouth of 
the adult would not lead us to expect the ex- 
istence of a gland, the secretion of which is 
usually obtained by the action of a soft mouth 
convertible into a sucking apparatus. 
Nevertheless a distinct mammary gland was 
described and figured by Meckel in 1826; and 
an organization of the lips and tongue of the 
young animal to correspond with it was sub- 
sequently described by Professor Owen in the 
Trans. Zool. Society, vol. i. p. 228, 1834. 
According to Meckel this gland is placed 
on the side of the abdomen between the pan- 
niculus carnosus, to which it adheres loosely, 
and the obliquus descendens abdominis, stretch- 
ing from the anterior and external margin of 
the pectoral muscle and inferior extremity of 
the sternum to the thigh. Its great size is 
merely one among the many instances which 
we meet of the comparative want of con- 
centration of individual organs in the lower 
as contrasted with the higher animals, for the 
secreting surface itself is much less extensive 
than in those animals in whom the whole organ 
is much less. 
The mammary glands of the Ornithorhyn- 
chus are peculiar for the absence of the nipple, 
a deficiency which is not met in any other 
class.. In the Cetacea it is so completely bu- 
ried and concealed that it has been described 
as absent, but it exists perfectly formed, 
buried in its protecting fissure. The defi- 
ciency in the first and concealment in the last 
* Linn. Trans. vol. xvii. 1828. 
