218 LECTURE IX. 



are peripheral ones, whether they arise from external or 

 internal parts, and only after a somewhat lengthened 

 course do they gradually reach the blood-vessels. In all, 

 interruptions are formed by the 1 lymphatic glands, and 

 since we know that the lymphatic vessels do not pass 

 through the glands as wide, tortuous, and interlacing 

 canals (p. 208), but that, after they have broken up into 

 fine branches, they enter into spaces which are filled with 

 cellular elements, it is manifest, that no pus-corpuscle 

 can pass a gland. 



This is a very important point of view which curiously 

 enough is generaUy overlooked, although it meets with 

 the best possible confirmation in the daily experience of 

 the practical physician. In proof of the inevitable ob- 

 struction to the passage of solid particles through the 

 lymphatic glands, a very pretty experiment is afforded 

 by a custom prevalent amongst the lower classes of our 

 population, the well-known practice of tattooing the arms 

 and occasionally other parts. When a workman or a 

 soldier has a number of punctures made upon his arm. 

 and arranged so as to represent letters, signs, or figures, 

 nearly always, in consequence of the great number of 

 punctures, some of the superficial lymphatic vessels are 

 injured. It could not indeed well happen otherwise than 

 that, when whole regions of skin are circumscribed by 

 the pricks of a needle, at least some few lymphatic ves- 

 sels should be hit upon. Afterwards a substance is rub- 

 bed in which is insoluble in the fluids of the body, such 

 as cinnabar, gunpowder, or the like, and which, remain- 

 ing in the parts, causes a permanent coloration of them. 

 But in the rubbing in a certain number of the particles 

 find their way into lymphatic vessels, are carried along 

 in spite of their heaviness by the current of lymph, and 

 reach the nearest lymphatic glands, where they are sepa- 

 rated by filtration. We never find that any particles are 



