314 COMPARATIVE AND HISTORICAL. 



responds to the process of filtration through animal membranes, i.e., the transudation contains 

 only those substances already present in the blood-plasma. The filtrate may even contain 

 more salts than the original thud, as is often the case with fluids containing crystalloid and 

 colloid bodies. Senator finds, in cases of oedema of the leg, that increase of the venous 

 pressure increases the proteids in the transudation, but causes no essential change in the 

 amount of the salts.] 



[(4) Ostroumoff found that stimulation of the lingual nerve not only causes the blood-vessels 

 of the tongue to dilate, but that the corresponding side of the tongue becomes cedematous. If a 

 solution of dilute hydrochloric acid or quinine ( 145) be injected into the duct of the sub- 

 maxillary gland, and the chorda tympani stimulated, there is no secretion of saliva, but the 

 gland becomes cedematous. In an animal poisoned with atropin, stimulation of the chorda 

 causes dilatation of the blood-vessels, although there is no secretion of saliva, nevertheless the 

 gland does not become cedematous (Hcidcnhain). As Brunton suggests, this experiment points 

 to some action of atropin on the blood-vessels which has hitherto been entirely overlooked.] 



204. COMPARATIVE PHYSIOLOGY. In the frog large lymph-sacs, lined with endothe- 

 lium, exist under the skin, while large lymph-sacs lie in relation with the vertebral column 

 one on each side separated from the abdominal cavity by a thin membrane, perforated with 

 ;stom;ita. This is the cysterna lymphatica magna of Panizza. Some amphibians and many 

 reptiles have under the skin large lymph-spaces, which occupy the whole of the dorsal region 

 of the body. All reptiles and the tailed amphibians have large elongated reservoirs for lymph 

 along the course of the aorta. The lymph-apparatus of the tortoise (fig. 218) is very extensive. 

 The osseous fishes have in the lateral parts of their backs an elongated lymph-trunk, which 

 reaches from the tail to the anterior fins, and is connected with the dilated lymphatic rootlets 

 in the base of the tail and in the fins. The largest internal lymph-sinus is in the region of the 

 "esophagus. Many birds possess a sinus-like dilatation or lymph-space in the region of the 

 tail. The lymph-spaces communicate with the venous system with valves properly arranged 

 usually in connection with the upper vena cava. Lymph-hearts have already been referred to 

 ( 201, 6). In carnivora the lymph -glands of the mesentery are united into one large compact 

 mass, the so-called " pancreas Asellii." 



205. HISTORICAL. Although the Hippocratic School was acquainted with the lymph 

 glands from their becoming swollen from time to time, and although Herophilus and 

 Erasistratus had seen the mesenteric glands, yet Aselli (1662) was the first who accurately 

 described the lacteals of the mesentery with their valves. Pecquet (1648) discovered the 

 receptaculum chyli ; Rudbeck and Thorn. Bartholinus the lymphatic vessels (1650-52); 

 Eustachius (1563) was acquainted with the thoracic duct, which Gassendus (1654) maintained 

 that he was the first to see; Lister noticed that the chyle became blue when indigo was injected 

 into the intestine (1671) ; Sommering observed the separation of fibrin when lymph coagulated; 

 Keiiss and Emmert discovered the lymph-corpuscles. The chemical investigations date from 

 the first quarter of this century ; they were earned out by Lassaigne, Tiedemann, Gmelin, and 

 others. The two last-named observers noticed that the white colour of chyle was due to the 

 presence of fatty granules. 



