330 ABSOBPTIOF. 



the deepening of the color when the fluid has been allowed to stand. The origin of these 

 red corpuscles has long been a subject of discussion. Their constant presence in lymph 

 or chyle discharged by fistulous openings has led to the opinion that they are normal 

 constituents of these fluids ; and this view has been adopted without reserve by those 

 who assume that the blood-corpuscles are formed from the white corpuscles, or leuco- 

 cytes. If this view of the formation of the corpuscular elements of the blood be adopted, 

 there is no good reason why red corpuscles should not be formed from the leucocytes in 

 the lymph and chyle as well as in the blood itself; particularly as the clear fluid of the 

 lymph and chyle contains nearly all the principles found in the plasma of the blood. On 

 the other hand, many physiologists regard the presence of red corpuscles as always acci- 

 dental ; and, in support of this view, Eobin brings forward the fact that red corpuscles are 

 never found in lymph taken from a portion of a vessel included between two ligatures. 

 This is certainly a very strong argument against the constant and normal existence of red 

 corpuscles in the lymph, particularly as the connection between the lymphatics and the 

 blood-vessels is very close, and all operations upon the lymphatic system involve dis- 

 turbances in the circulation. There is no positive evidence of the formation of red cor- 

 puscles from the leucocytes ; and, if it be the fact that red corpuscles never exist in lymph 

 taken from a portion of a lymphatic vessel included between two ligatures, it is fair to 

 assume that the presence of these corpuscles in lymph and chyle is accidental, and that 

 they are always derived from the blood. 



Lymph has no decided or characteristic odor. It is very slightly saline in taste, being 

 almost insipid. Its specific gravity is much lower than that of the blood. Magendie 

 found the specific gravity in the dog to be about 1022. Kobin states that the specific 

 gravity of the defibrinated serum of lymph is 1009. In some recent analyses, by 

 Dahnhardt, of the lymph taken from dilated vessels in the leg, in the human subject, the 

 specific gravity was only 1007. The exceedingly low specific gravity in the last instance 

 would rather lead to the opinion that the fluid was not entirely normal. The difficulty 

 in obtaining this fluid in a perfectly normal condition from the human subject has ren- 

 dered it impossible to ascertain its normal specific gravity, even approximative^ ; but it 

 evidently possesses a density much inferior to that of the blood. The reaction of the 

 lymph is constantly alkaline. 



A few minutes after discharge from the vessels, both the lymph and chyle undergo 

 spontaneous coagulation. According to Colin, the fluid collected from the thoracic duct 

 in the large ruminants coagulates at the end of five, ten, or twelve minutes, and sets into 

 a mass having exactly the form of the vessel in which it is contained. Colin states that 

 the clot is tolerably consistent, but that there is never any spontaneous separation of 

 serum. This may be the fact with regard to the lymph and the chyle of the large rumi- 

 nants, but, in the observations of Dalton, who operated upon dogs and goats, after a few 

 hours' exposure, the clot contracted to about half its original size, precisely like coagu- 

 lated blood, expressing a considerable quantity of serum. In one instance, in the dog, the 

 volume of serum, after twenty-four hours of repose, was about twice that of the contract- 

 ed clot. Milne- Edwards, quoting from an unpublished memoir presented by Colin to the 

 Academy of Sciences, in 1858, states that the lymph does not coagulate in the vessels, 

 even when the circulation is interrupted. This may be the case under ordinary condi- 

 tions, when the vessels are simply tied ; but it was found by Flandrin, that coagulation 

 obstructed the tubes which he introduced into the thoracic duct so completely that he 

 was able to obtain but a small quantity of fluid ; a difficulty which is also mentioned by 

 Colin, who states that " the clearing of the tube rarely suffices to reestablish the flow, for 

 the coagnlum formed in the tube is prolonged for a greater or less distance into the in- 

 terior of the thoracic duct." Coagulation of lymph in the vessels during life, if it occur 

 at all, must be exceedingly infrequent, notwithstanding that the flow of lymph and chyle 

 is very slow and irregular, as compared with the circulation of the blood, and is subject, 

 probably, to frequent interruptions. 



