LYMPH AND CHYLE. 339 



were performed upon young goats and dogs, and the general results with regard to the 

 quantity of fluids discharged closely corresponded with those obtained by Colin. The 

 operation of making the fistula in goats is not very difficult, all that is necessary being 

 to cut down upon the subclavian vein at the point where the duct empties into it, and to 

 fix in it a tube of appropriate size ; but, in dogs, the vessels are more deeply situated, and 

 the operative procedure is much more tedious. This, however, is the only way in which 

 lymph and chyle can be obtained from the lower animals in any considerable quantity. 



Quantity of Lymph. Although the experiments just described might at first seera 

 sufficient to give a pretty clear idea of the entire quantity of lymph discharged into the 

 venous system, it is evident that the conditions of the circulation of this fluid must be so 

 seriously modified by the establishment of a fistula, that the results thus obtained are far 

 from being entirely satisfactory. In the first place, Colin found that the canal, at its 

 junction with the subclavian vein, was seldom single ; and, in many of his observations 

 in which a very large quantity of liquid was obtained, there were several vessels of nearly 

 equal size emptying into the venous system. In the experiment to which we have 

 referred, however, the opening was single ; and the quantity of fluid obtained represented 

 all that passed up the thoracic duct during the time that the observation was continued. 

 As we should naturally expect, the discharge of liquid was subject to certain variations, 

 its maximum corresponding with the period of greatest activity in digestion and absorption. 



It is not possible to estimate the influence of the unobstructed discharge of lymph 

 and chyle by a fistulous opening upon the absolute quantity which passes out of the 

 canal ; and, in the natural course of the circulation, there is a certain amount of obstruc- 

 tion to its entrance into the vein, which might sensibly retard the current. 



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 pro- 

 duced in the twenty-four hours in a man weighing one hundred and forty pounds is from 

 six to six and a half pounds. And, again, reasoning from experiments made upon dogs 

 eighteen 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 between three and a half and 

 four pounds (3-864 Ibs.). These estimates can only be accepted as approximative, 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 physiological 

 variations in the quantity of lymph. Collard de Martigny made a series of elaborate 

 investigations a number of years ago, with regard to the effects of starvation upon the 

 constitution and the quantity of the lymph. He found the lymphatics always distended 

 with fluid in dogs killed after two days of total deprivation of food. This condition con- 

 tinued during the first week of starvation ; but, after that time, the quantity in the ves- 

 sels 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 lymphatics 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 transparent and colorless or of a slightly yellow- 

 ish 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. Miscroscopical 

 examination shows that this reddish color is dependent upon the presence of a few blood- 

 corpuscles, which are entangled in the clot as the lymph coagulates, thus accounting for 



