161 



XXVI. LETTER FROM M. RUSCONI TO PROFESSOR BRESCHET, ON A 



NEW METHOD OF INJECTING THE LYMPHATIC SYSTEM OF REPTILES?.* 



PROFESSOR COSTA handed to me a short time since the letter with which 

 you have been kind enough to honour me. I am delighted to see you 

 have undertaken, at my particular request, to make some researches 

 on the lymphatic vessels of reptiles ; this subject well deserves your 

 attention, and I feel satisfied your investigations will tend to the ad- 

 vancement of science. You desire to know the anatomical process of 

 which I make use, for injecting the lymphatic vessels of reptiles ; I 

 hasten to satisfy you : 



In my first letter, after having briefly shown the chief results obtained 

 by my experiments, and having also shown the singular disposition of 

 the arteries enclosed within the veins, I believe I stated that I employ 

 a small syringe in place of the injecting tube of Walter, modified by 

 Scernmering, and a fluid coloured red or white in the place of mercury 

 but I have not at all directed attention to the small instrument I use, 

 and which is most essential, it is a kind of trochar, of which the 

 canula is formed from the quill of the wing feather of the quail or 

 partridge, the trochar being a tolerably large sized needle of five or six 

 centimetres in length, and of which the point has three facets. It is on 

 this small instrument that the successful result of the operation most 

 frequently depends : I also take great precaution to sharpen its point 

 well upon a hone, and also that the anterior extremity of the tube is 

 adapted exactly to the needle. 



When I am desirous of filling with injection the lymphatic system of 

 a lizard, salamander, or tortoise, I seize with a small pair of forceps the 

 mesentery close to the vertebral column where the reservoir of the chyle 

 is situated, and I introduce into it the point of the trochar, I then re- 

 tain the quill and withdraw the needle from the tube after having thus 

 withdrawn it, and I think it necessary, the tube is pushed forward, 

 taking great care that the reservoir of the chyle has not been injured 

 in any other part. 



This done I seize with the small forceps the quill, and introduce into 

 it the small extremity of the syringe, and push the piston with a force 

 always decreasing. It is by this process the arterial and venous systems 



* From the Annales des Sciences Naturelles. February, 1842, p. iii. 



VOL. II. M 



