164 ON INJECTING THE LYMPHATIC SYSTEM OF REPTILES. 



must be admitted, they are not altogether exempt at certain points 

 from these dilatations rendering their surfaces unequal and undulating. 

 In this relation, they may be compared to veins, which they resemble in 

 many other points and of which they are perhaps but a modification. 

 As it is, I have frequently recognized something analogous on veins, 

 both on the trunks, and on the divisions of small calibre. My experi- 

 ence on this particular, has probably some value, for professional anato- 

 mists are not altogether unaware that I performed numerous experi- 

 ments on veins, and that I commenced publishing the history of this 

 important section of the vascular system, which I am in hopes of con- 

 tinuing at some future period. 



M. Rusconi generously gives us his operative process for making in- 

 jections of lymphatic vessels ; at the same time he forgets to make us 

 acquainted with the nature and composition of the matter he employs 

 to distend the vessels. We will now give in a few words, with a view 

 of supplying this deficiency, that which the talented zootomist has 

 omitted to mention. 



Independently of the substances mentioned in the Dissertation of M. 

 Dumeril, or in the Manual of Anatomy by E. A. Lauth, we have fre- 

 quently employed with success, milk, isinglass variously coloured either 

 with vermillion, cochineal, chrome yellow, prussian blue, indigo, &c., 

 or the alcoholic solution of gum-lac, coloured with the substances just 

 alluded to. Spirit varnish, or spirit of turpentine, and sometimes dia- 

 chylon plaster, made liquid by heat in a sand-bath, are all of them 

 methods of which the anatomist may take advantage. 



It has been for a long time observed that injections in which the co- 

 louring substance is in suspension, are, in many cases insufficient, be- 

 cause in the very small vessels, there is a separation between the vehicle 

 and colouring principle. I desired then to possess a colouring substance 

 soluble in water, oil, or alcohol ; in short a soluble matter. I have dis- 

 covered this colouring matter, it is that which chemistry affords abun- 

 dantly to commerce, at a low price, and is extracted from campeachy, 

 fernambouc, or sandal woods. 



The colouring matter of campeachy wood easily dissolves in water 

 and in alcohol ; it is so penetrating that it becomes rapidly spread 

 throughout the vascular networks. The sole inconvenience of this kind 

 of injection is, that it cannot be made to distend any except the most 

 delicate vessels, and that its ready penetration does not admit of distin- 

 guishing between arteries, veins, and lymphatics. 



Lastly, there is another process of injection which we frequently em- 

 ploy, and which may be termed the chemical process. The process 



