ITS ORIGIN. 303 



than of the blood-vessels, since we are much less acquainted with 

 the anatomy of the former than of the latter. We referred, in our 

 remarks on the quantity of chyle formed in a definite time, to the 

 reasons, which render the amount of fluid escaping from the main 

 branch of a lymphatic system, an inefficient criterion of the quantity 

 of this juice formed within any given period. The following facts 

 may, however, aid us in arriving at an approximate idea of the 

 quantity of lymph formed or flowing into the vessels : Collard de 

 Martigny* found that 9 grains of this fluid flowed in 10 minutes 

 from the thoracic duct of a rabbit which had fasted for 24 hours. 

 J. Miiller assumes the capacity of the four lymphatic hearts which 

 he discovered in the frog, at about 4 cubic lines, and as these would 

 make about 60 pulsations in a minute, these four lymphatic hearts 

 would drive about 240 cubic lines of lymph into the veins in this 

 period, provided that they are completely emptied at every con- 

 traction, which, however, is not the case. Moreover, the lymphatic 

 system is of far more relative importance in frogs and cold-blooded 

 animals than in those in which there is warm blood. 



The origin of the lymph has been referred by all physiologists 

 to the juice which flows from the capillaries into the parenchyma 

 of the organs, either for their nutrition or for the formation of the 

 secretions. Although physiologists had previously shown that the 

 character and quantity of the lymph depend upon the fluid con- 

 veyed through the capillaries, and transuded from them, these views 

 have recently been fully confirmed by Noll. It therefore now only 

 remains for the chemist to institute an accurate comparison of the 

 blood-plasma, the parenchymatousfluid, the secretions and the lymph, 

 in order to deduce the chemical equations giving the scientific ex- 

 pression for the processes which give rise to the formation of the 

 lymph. We are, however, still very far distant from the attainment 

 of this aim, towards which our chemical investigations ought to be 

 directed ; for even if we assume that the differences in the transuding 

 blood-plasma and the resorbed lymph can be investigated with che- 

 mical accuracy in the same individuals, we are yet unable to draw any 

 certain conclusions in reference to the metamorphoses which the 

 blood-plasma undergoes in each individual organ, or even generally, 

 or to trace the origin of the separate constituents of the lymph. 

 Moreover the lymph which is accessible to chemical inquiry by 

 means of the physiological aids at present at our command, cannot 

 be regarded as the product of the nutrition of these organs. For 

 there is not only a larger quantity of plasma exuded through the 

 * Journ. de Physiol. T. 8, p. 266. 



