THE RED PARTICLES. 283 



scribed; where the arteries which are spread out in form of 

 network upon the sides of the cells secrete from the blood the 

 vesicular portion, and that when thus perfectly made, the 

 lymphatic vessels which originate from the cells absorb them, 

 and convey them thence into the thoracic duct, and so into the 

 blood-vessels. 



SECT. 99. That the spleen does secrete somewhat, is evident 

 from the change observable in blood drawn from the splenic 

 vein, which is distinguished by this remarkable property, that 

 it will not coagulate like blood taken from other veins (CXLVII); 

 the reason we apprehend is, because the coagulable lymph is 

 employed by nature in the formation of the red vesicle ; it re- 

 mains therefore fluid until the thinner parts have evaporated, 

 leaving* the red particles a dry mass. 



SECT. 100. Fourthly, we have frequently examined blood 

 taken from the splenic vein, but could never distinguish any 

 central particles in it (CXLVIII). 



SECT. 101. Fifthly, in every animal which has red blood a 

 spleen is found; but in those animals which have not red 

 blood the spleen is wanting (CXLIX). 



SECT. 102. Lastly, we find that vast quantities of the red 

 particles of the blood are brought from the spleen by the 

 lymphatic vessels which originate in its substance, and for this 

 reason we have called these lymphatic vessels the excretory 

 ducts of the spleen. 



SECT. 103. That the red particles of the blood are com- 

 pletely formed by the spleen we have therefore as strong 



(CXLVII.) See Note cxxxn, p. 269, and Note CLI, p. 289. 



(CXLVIII.) Contrary to the statement in the text, and to the similar 

 observation of Dr. Simon, 3 I have more than once seen pale corpuscles 

 abundantly in the blood of the splenic vein. They did not differ in struc- 

 ture or size from the pale globules in the blood of the heart ; nor could I 

 observe any difference between the red corpuscles from the splenic vein 

 and from the heart, examined at the same time from the same animal ; 

 and the central spot 5 was observed as well in the red corpuscles of the 

 splenic blood as in those from the heart. In one trial I saw the nuclei 

 as usual in blood-corpuscles taken from the spleen of a goose. 



(CXLIX.) The spleen is said to be wanting in two or three cyclosto- 

 matous fishes : see Note cxxxm, p. 2/3. 



* Animal Chemistry, tr. for the Syd. Soc. b See Note xcvi, p. 216. 

 vol. i, p. 202, 8vo, Lond. 1845. 



