PROPERTIES OF THE BLOOD. 427 



so that Mr. Lane's view is probably the correct one. Even if the Blood-discs 

 are not introduced into the Lymphatics during the operation of exposing tha 

 Thoracic Duct, it may not be considered as improbable that, in those animals 

 in which the Lymphatics have several communications with the Veins, they 

 should naturally obtain an entrance in various parts of the system. Such 

 communications, according to Gerber, decidedly exist in the Horse ; and it is 

 in the Chyle of that animal, that the rosy tint, and the Blood-corpuscles which 

 occasion it, have been chiefly observed. 



509. The following table, slightly modified from that of Gerber, presents 

 in a concise form, a view of the relative proportions of the three chief ingre- 

 dients in the Chyle, in different parts of the absorbent system, and thus gives 

 an idea of its advance in the process of assimilation. 



In the afferent or periphe- ("Fat, in maximum quantity (numerous fat or oil 



ral Lacteals (from the In-J g lobules > 



x i v T./T < Albumen m minimum quantity. 



SET) Few or no ch y le - COT P scks - 



In the efferent or central 

 LacteaJs (from the Me- 

 senteric glands to the 

 Thoracic Duct). 



In the Thoracic Duct. 



JFibrin, almost entirely wanting. 



"Fat, in medium quantity (fewer oil-globules). 



Albumen, in maximum quantity. 



Chyle-corpuscles very numerous, but imperfectly 

 developed. 



_Fibrin, in medium quantity. 



"Fat, in minimum quantity (fewer or no oil- 

 globules). 



Albumen, in medium quantity. 



Chyle-corpuscles numerous, and more distinctly 

 cellular. 



_Fibrin, in maximum quantity. 



IV. Physical and Vital Properties of the Blood. 



570. The Blood, whilst circulating in its vessels, is composed of a fluid, in 

 which a large number of corpuscles or particles of a red colour are suspended. 

 The fluid portion, which is known under the name of Liquor Sanguinis, 

 essentially consists of Fibrin and Albumen, with Saline matter, dissolved in 

 water ; and this, when effused without an intermixture of corpuscles, is known 

 under the name of Coagulable Lymph. The red Blood-particles (commonly, 

 but erroneously, termed globules] are flattened discs, which, in Man and most 

 of the Mammalia, have a distinctly circular outline. In the discs of Human 

 blood, when examined in its natural condition, the sides are somewhat con- 

 cave ; and there is a bright spot in the centre, which has been regarded by 

 many as indicating the existence of a nucleus, although it is in reality due 

 simply to the greater thinness of the disc at that part. The form of the disc 

 is very much altered by various reagents ; for the membrane which composes 

 its exterior is readily permeable by fluids ; so that, if the discs be put into 

 water, a powerful endosmose takes place towards the interior, causing the 

 particles to assume a globular form ; whilst, if they be treated with syrup, or 

 with a thick solution of albumen, they will be more or less completely emptied, 

 so as to present a shrunken appearance. Hence, in examining the Blood, it is 

 necessary to dilute it with a fluid as nearly as possible of the same character 

 with ordinary serum.* In regard to the existence of a nucleus in the corpus- 



* By Wagner, the filtered serum of frog's blood is recommended for this purpose. 

 Weak solutions of salt or sugar, and urine, answer tolerably well ; but Mr. Gulliver re- 

 marks that all addition must be avoided when it is intended to measure the corpuscles, 



