338 GENERAL ANATOMY OF THE ABSORBENT SYSTEM. 



laries. In the absence, therefore, of all positive knowledge 

 upon the subject, there has been much room for speculation ; 

 — some believing them to originate from the arteries, — some 

 by open mouths or gaping orifices, — and some by a net-work, 

 in which the vessels, tracing them towards their origin, seem to 

 anastomose again and again with one another. 

 — The first opinion was derived from the fact first noticed by 

 Cowper, Cheselden, and Ferrein, that in making delicate 

 injections of various parts of the body, the injecting . matter, 

 will pass occasionally from the arteries into the lymphatics; 

 and Breschet* has observed the same result when an in- 

 jection has been pushed at the same time in several of the 

 smaller branches of the veins, in the direction of their roots. 

 The researches of Panissa,f Miiller, and others, have shown that 

 this takes place but sparingly in any part of the body, and in gen- 

 eral, only when considerable force is used, and that in some por- 

 tions it cannot be effected at all. So that this communication 

 with the blood-vessels, cannot be looked upon as evincing the com- 

 mon mode of origin of the absorbent vessels, which are so very 

 numerous ; in many instances it is probably produced by a lace- 

 ration of the tissues from the force of the injection, by which means 

 some of the injected fluid insinuates itself into a ruptured absorbent 

 vessel. It is even possible that a communication may be made by 

 forcing a passage through the pores in the parietes of the vessels, 

 as Fohman has suggested. 



— The origin by open mouths or gaping orifices, which was main- 

 tained by Lieberkuhn, Cruikshank, Cruveilhier, Magendie, and 

 others, but only with respect to the lacteals, does not appear to 

 be better founded. The orifices they saw probably resulted from 

 a laceration of the parts, since Rudolphi, Panissa, Breschet, 

 Fohman, and Lauth, in experiments made expressly to deter- 

 mine this point, have never observed them as a normal state, 

 either in the injection of dead bodies, or in the microscopical 

 observations of the transparent parts of living animals, or in 

 observations like that of Cruikshank, made by Lauth and 



* Le Systeme Lymph, etc., par G. Breschet. Paris, 1836 — 

 t Observationes Antrop. Zoolomico Fisiologiche. By Prof. Panissa, Pavia, 

 1833.— 



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