252 
has a relation to the aquatic mode of 
life, the whole surface of the body 
being constructed with the view of 
avoiding friction. The mammary gland 
in the Ornythorhynchus consists inter- 
nally of pyriform cocal pouches, with 
their bases turned towards the skin, 
their apices communicating with short 
excretory ducts; the walls of these 
pouches are thick and the cavities nar- 
row. As regards simplicity of the in- 
ternal arrangement of the gland, that in 
the common porpoise, where the cells 
and milk tubes are large and diffused, 
may be placed next in order to the 
Ornithorhyrchus. 
There is no reason for supposing 
that there is any essential departure 
from this kind of arrangement of the 
secreting portion of the gland in dif- 
Fig. 78. 
One of the clefts a little open, to shew the end of the 
mamill@ buried in it. 
Fig. 79. 
Shews the cleft more open, exhibiting the nipple and 
its orifice poh iors into it. These clefts are placed 
tn their natural direction in the long axis of the 
animal, but fig. 77 is not. 
ferent animals, the cellular or vesicular having 
been met with in all instances where this 
gland has been carefully injected and un- 
ravelled. But the efferent ducts vary con- 
siderably. We learn from Sir A. Cooper that 
the cow, the ewe, the goat, the guinea-pig, and 
the porpoise, have only one tube in each 
teat. The pig has two, the rhinoceros has 
twelve, and the hare and rabbit and the cat 
and bitch several. “ In the Graminivora the 
reservoirs are enormously large, in the Carni- 
vora comparatively small. In the pig there is 
scarely any reservoir; in the porpoise the great 
enlargement of the milk-tube is a substitute for 
the reservoir.” 
MAMMARY GLANDS. 
3 the situation of the clefts in the skin of 
which contain the mamilla, and which are placed on each 
of the anus and os externum vaginge. They are ¢ 
smaller than nature in this drawing, but figs. 78 and 79.4 
the natural size. 
Fig. 77. 
= me ary 
So 
Pe oe 5 Fo SS = 
ss 
Morbid anatomy.—It must be clearly un 
stood by our readers that we do not intend te 
more than a mere outline of its diseases, ¢ 
must refer them for more ample information 
the admirable works of Sir A. Cooper 3 
others. The diseases of the breast have be 
divided by Sir A. Cooper into three class 
“‘ first, those which are the result of comm 
inflammation, whether it be acute or chron 
Secondly, into complaints which arise fro 
peculiar or specific action, but which are 1 
malignant, and do not contaminate other 
tures. Thirdly, into those which are not 
founded on local, malignant, and specific a 
tions, but which are connected with a pecu 
and unhealthy state of the constitution. a 
Simple inflammation of the breast, like 
flammation in every organ where its progre 
would rapidly prove destructive to its essen 
structure, is attended with excessive and ii 
ordinate pain, and thys gives such warnin 
the danger that it cannot be disregarded by 
sufferer. The fibrous protective covering of 
gland, like that of the testicle, prevents inordii 
swelling, but occasions greater hardness to: 
touch. This inflammatory action, usually 4 
unequivocal in its appearance, very rapidly ¢ 
velopes pus ; the abscess following is troul 
some and extremely obstinate in cure ; chro 
abscess does, however, occasionally oceur, 
absence of all the usual symptoms of infla 
mation masks the character of the disease 
gives rise to the suspicion that it is a ma 
tumour requiring extirpation. Sir Astle; 
lates some cases which came under his 
in which the sense of fluctuation indicate 
him the true character of the disease, 
others in which the extirpating knife of 
surgeon was only arrested by the flow of p 
This same author describes such occasi 
distension of one of the lactiferous tubes cau 
by chronic inflammation and obliteration of 
aperture as to simulate chronic abscess. T 
breast is liable to what has been called hyda 
disease, of which there are four kinds, one 
a malignant nature; the other three are not) 
The first has been designated by Sir A. Coope 
cellulous hydatids; the second is the sera i 
tumour of Sir B. Brodie; the third is the ani 
