PROPERTIES AND COMPOSITION OF LYMPH. 295 



the first to give any clear idea of the quantity of liquids lymph and chyle 

 which pass through the thoracic duct. In an observation upon a cow of 

 medium size, he succeeded in collecting, in the course of twelve hours, 105-3 

 Ibs. (47,963 grammes) ; and he stated that a very much greater quantity can 

 be obtained by operating upon ruminants of larger size. 



According to the estimates of Dalton, deduced from his own observations 

 upon dogs and the experiments of Colin upon horses, the total quantity of 

 lymph and chyle produced in the twenty-four hours in a man weighing one 

 hundred and forty- three pounds (65 kilos.) is about 6' 6 pounds (3,000 

 grammes). And again, reasoning from experiments made upon dogs thir- 

 teen hours after feeding, when the fluid which passes up the thoracic duct 

 may be assumed to be pure, unmixed lymph, the total quantity of lymph 

 alone, produced in the twenty-four hours by a man of ordinary weight, 

 would be about 4-4 pounds (2,000 grammes). These estimates can be accepted 

 only as approximate, and they do not indicate the entire quantity of lymph 

 actually contained in the organism. 



There are no very satisfactory recent researches with regard to the physi- 

 ological variations in the quantity of lymph. Collard de Martigny found 

 the lymphatics always distended with fluid in dogs killed after two days of 

 total deprivation of food. This condition continued during the first week 

 of starvation ; but after that time, the quantity in the vessels gradually 

 diminished, and a few hours before death, the lymphatics and the thoracic 

 duct were nearly empty. In comparing the quantity of fluid in the lymphat- 

 ics of the neck, during digestion and absorption, with the quantity which they 

 contained soon after digestion was completed, the same observer found that 

 while digestion and absorption were going on actively, the vessels of the 

 neck contained scarcely any fluid ; but the quantity gradually increased after 

 these processes were completed. 



Properties and Composition of Lymph. Lymph taken from the vessels 

 in various parts of the system, or the fluid which is discharged from the 

 thoracic duct during the intervals of digestion, is either perfectly transpar- 

 ent and colorless or of a slightly yellowish or greenish hue. When allowed 

 to stand for a short time, it becomes faintly tinged with red, and frequently 

 it has a pale rose-color when first discharged. Microscopical examination 

 shows that this reddish color is dependent upon the presence of a few red 

 blood-corpuscles, which are entangled in the clot as the lymph coagulates, 

 thus accounting for the deepening of the color when the fluid has been 

 allowed to stand. 



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. According to Robin, the specific gravity of the defibrinated serum of 

 lymph is 1009. In analyses by Dahnhardt, of the lymph taken from dilated 

 vessels in the leg, in the human subject, the specific gravity was 1007. 



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

 chyle undergo coagulation. This process, as regards the chemical changes 



