252 



MAMMARY GLANDS. 



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 py'riform ccecal 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 

 Ornithorhyr.chus. 



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. 



Fig. 77. 







One of the clefts a little open, to shew the end of the 

 mantilla; buried in it. 



Fig. 79. 



Shews the cleft more open, exhibiting the nipple and 

 its orifice projecting into it. These clefts are placed 

 in their natural direction in the long axis of the 

 animal, but Jig. 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 die porpoise the great 

 enlargement of the milk-tube is a substitute for 

 the reservoir.'' 



Shews the situation of the clefts in the skin of the Porpoise 

 which contain the mamillcB, and which are placed on each side 

 of the anus and os externum vayinca. They are considerably 

 smaller than nature in this drawing, but Jigs. 78 and 79 are of 

 the natural sixe. 



Morbid anatomy. It must be clearly under- 

 stood by our readers that we do not intend to give 

 more than a mere outline of its diseases, and 

 must refer them for more ample information to 

 the admirable works of Sir A. Cooper and 

 others. The diseases of the breast have been 

 divided by Sir A. Cooper into three classes; 

 " first, those which are the result of common 

 inflammation, whether it be acute or chronic. 

 Secondly, into complaints which arise from 

 peculiar or specific action, but which are not 

 malignant, and do not contaminate other struc- 

 tures. Thirdly, into those which are not only 

 founded on local, malignant, and specific ac- 

 tions, but which are connected with a peculiar 

 and unhealthy state of the constitution." 



Simple inflammation of the breast, like in- 

 flammation in every organ where its progress 

 would rapidly prove destructive to its essential 

 structure, is attended with excessive and in- 

 ordinate pain, and thus gives such warning of 

 the danger that it cannot be disregarded by the 

 sufferer. The fibrous protective covering of the 

 gland, like thatofthetesticle,prevents inordinate 

 swelling, but occasions greater hardness to the 

 touch. This inflammatory action, usually very 

 unequivocal in its appearance, very rapidly de- 

 velopes pus ; the abscess following is trouble- 

 some and extremely obstinate in cure ; chronic 

 abscess does, however, occasionally occur, and 

 absence of all the usual symptoms of inflam- 

 mation masks the character of the disease and 

 gives rise to the suspicion that it is a malignant 

 tumour requiring extirpation. Sir Astley re- 

 lates some cases which came under his notice 

 in which the sense of fluctuation indicated to 

 him the true character of the disease, and 

 others in which the extirpating knife of the 

 surgeon was only arrested by the flow of pus. 

 This same author describes such occasional 

 distension of one of the lactiferous tubes caused 

 by chronic inflammation and obliteration of its 

 aperture as to simulate chronic abscess. The 

 breast is liable to what has been called hydatid 

 disease, of which there are four kinds, one of 

 a malignant nature ; the other three are not so. 

 The first has been designated by Sir A. Cooper 

 cellulous hydatids ; the second is the sero-cystic 

 tumour of Sir B. Brodie; the third is the ani- 



