234 



MAMMALIA. 



are usually met with. The cervical, bronchial, 

 and mesenteric glands are those most frequently 

 affected, but all the absorbent glands are very 

 often engaged. Louis states that in phthisis* 

 the relative frequency of tuberculization of these 

 glands is as follows, the mesenteric, meso- 

 coecal, meso-colic, cervical, lumbar, and axil- 

 lary glands, and that the bronchial glands are 

 as often affected as the mesenteric. 



The glands affected in children observe pretty 

 nearly the same order as regards the relative 

 frequency of the affection. They are always 

 much enlarged, and frequently closely adherent 

 to each other or neighbouring textures; and the 

 cheesy matter either infiltrates the tissue or is 

 deposited in small poitions in the glands. In 

 an infant, which I had lately under my care in 

 conjunction witn Mr. Holt, it was found, upon 

 post-mortem inspection, that the severe cough 

 with remittent dyspnoea, under which the child 

 sunk, was owing to a mass of enlarged bron- 

 chial glands, of the size of a hen's egg, rilled 

 with cheesy matter, pressing on the primary 

 bronchi and on the pulmonary plexus of 

 nerves. 



Cancer, melanosis, and encepha'.oid matter 

 are frequently found in these bodies, especially 

 when other organs have been similarly affected. 

 Deposits of calcareous matter are likewise often 

 met with in them, and, as far as my experience 

 goes, in none more frequently than in the bron- 

 chial glands ; these deposits occur generally in 

 old subjects; they consist of phosphate of lime. 

 It has been suggested that this calcareous phos- 

 phate might be derived from the earthy matter 

 of the bones ; and Andral relates two remark- 

 able cases in which there was a coincidence 

 between the deficiency of a certain quantity 

 of osseous matter where it should naturally be 

 deposited and its deposition in the lymphatic 

 system. In one, a boy aet. 16, the bronchial, 

 mesenteric, and pelvic glands were occupied 

 by calcareous concretions, and his lungs also 

 contained them ; there was also an abscess in 

 one of the iliac fossae, with erosion and de- 

 struction of the os ilii. In a second case, a 

 woman, aet. 33, who died of acute pleuritis, 

 supervening upon a chronic pulmonary affec- 

 tion, the bodies of six vertebrae, the last dorsal 

 and five lumbar, were found destroyed, and cal- 

 careous concretions were found in the cervical, 

 thoracic, bronchial, abdominal, pelvic, axillary, 

 and inguinal glands. 



The black matter which is so often found in 

 the bronchial glands must not be confounded 

 with melanoid matter. We seldom examine a 

 body that has passed adult age without finding 

 more or less of this matter in the bronchial 

 glands, derived doubtless from the pulmonary 

 black matter, which is conveyed to these glands 

 by the pulmonary lymphatics. 



The changes which occur in the lymph itself 

 have not as yet received any attention from pa- 

 thologists. This fluid is, however, occasionally 

 either mixed with or replaced by others in the 

 lymphatic vessels. Cases are on record (Ma- 

 jendie, Dupuytren) in which it is stated that 



* Dr. Cowan's translation, p. 73. 



the lymphatics in the neighbourhood of san- 

 guineous effusions into the pleura and perito- 

 neum have been filled with blood, and that 

 pus had been absorbed into them from a neigh- 

 bouring abscess. Such cases require confirma- 

 tion with our present improved means of ob- 

 servation, as it is difficult to understand how 

 particles so large as the blood corpuscles, or 

 the globules of pus, could have permeated the 

 coats of the absorbent vessels. In future the 

 microscope must be brought to our aid in the 

 examination of such cases. Authors relate 

 likewise that bile has been found in the lym- 

 phatics of the liver and in its neighbourhood, 

 in cases where the flow of that fluid has been 

 obstructed, (Mascagni, Saunders ;) and Tiede- 

 mann states that in dogs, in which he had tied 

 the hepatic duct, the biliary secretion likewise 

 made its way into the lymphatics. Earthy 

 matter, as in the glands, has also been found 

 in the vessels themselves, and the tubercular, 

 encephaloid, or cancerous matter has likewise 

 been met with stopping up these vessels. 



For Bibliography, see that of ABSORPTION. 



(R. B. Todd.) 



MAMMALIA. (Lat. Mamma, a teat ; Ger. 

 Saugetkiere ; Fr. Mammiferes ; Eng. J\Ium- 

 mali>.) The most highly organized class of 

 animals, distinguished outwardly by a total or 

 partial covering of hair, and generally by 

 having external teats or mammae, whence the 

 name. Mammals always possess mammary 

 glands, and suckle their young ; the foetus is 

 developed in the womb ; their leading anato- 

 mical character is to have lungs composed of a 

 highly vascular and minutely cellular structure 

 throughout, and suspended freely in a thoracic 

 cavity, separated by a muscular and tendinous 

 septum or diaphragm from the abdomen. 



Mammals, like birds, have a heart composed 

 of two ventricles and two auricles : they respire 

 quickly, and have warm blood ; inspiration 

 is performed chiefly by the agency of the dia- 

 phragm : the right auriculo-ventricular valve is 

 membranous, at least never entirely fleshy ; 

 and the aorta bends over the left, never over the 

 right bronchial tube. The primary branches of 

 the aorta are given off, not immediately after, 

 but at a little distance from its origin, and 

 there is less constancy in the order of then- 

 origin than in birds : the phrenic arteries, 

 the coeliac axis, and the superior mesenteric ar- 

 tery are always branches of the abdominal 

 aorta, which terminates by dividing beyond the 

 kidneys into the iliac arteries, from which 

 spring both the femoral and ischiadic branches. 

 The caudal or sacro-median artery, which in 

 some long-tailed Mammals assumes the cha- 

 racter of the continued trunk of the aorta, 

 never distributes arteries to the kidneys or legs, 

 as in birds. The kidneys are nourished, and 

 derive the material of their secretion, exclusively 

 from the arterial system : their veins are sim- 

 ple, commencing by minute capillaries in the 

 parenchyma, and terminating generally by a 

 single trunk on each side, in the abdominal 



