CHAPTER XXL 233 



stimulate the contraction of tlie vessels, so that frequently it is very 

 difficult to get the injection in. In these cases it may be advisable 

 to use a vaso-dilator. The animal may be anaesthetised with a 

 mixture of ether and nitrite of amyl, and finally killed with pure 

 nitrite. Or, after killing by nitrite, a little nitrite of amyl in salt 

 solution may be injected before the injection mass is thrown in. 

 In any case it is advisable to add a little nitrite to the mass just 

 before using. The relaxing power is very great (see OVIATT and 

 SARGENT, in St. Louis Med. Journ. } 1886, p. 207 ; and Journ. Roy. 

 Mic. Soc., 1887, p. 341). 



BAYLISS (in personal communication) suggests for prevention of 

 coagulation, to wash out in citrate of soda (4 per cent.) instead of 

 75 NaCl, or to add J per cent, oxalate of calcium to -75 per cent. 

 NaCl. To relax arterial walls, add sodium nitrite 1 in 500 to the 

 washing out fluid. 



Or, morphia may be added to the injection mass, or 1 per cent. 

 of lactic acid. MOZEJKO (Zeit. wiss. Mik., xvi, 1909, p. 545) prefers 

 a saturated solution of neutral Peptonum siccum, which has the 

 advantage of hindering coagulation. For warm-blooded animals 

 the mass should be warmed to body-temperature ; and in all 

 cases masses that tend to dehydrate tissues should be avoided if 

 possible. 



ROBIN'S Masses. 



474. ROBIN'S Gelatin Vehicle (Traite, p. 30). One part of gelatin 

 soaked and melted in 7, 8, 9, or even 10 parts of water, on a water- 

 bath. 



This vehicle, like all gelatin masses, is liable to be attacked by 

 mould if kept long ; camphor and carbolic acid do not suffice to 

 preserve it. Chloral hydrate 2 per cent, is said to do so. 



475. ROBIN'S Glycerin-Gelatin Vehicle (Traite, p. 32). Dissolve 

 in a water-bath 50 grins, of gelatin in 300 grms. of water," in which 

 has been dissolved some arsenious acid ; add of glycerin 150 grms., 

 and of carbolic acid a few drops. Unlike the pure gelatin vehicles, 

 this mass does keep indefinitely. 



FKANKL (Zeit. f. wiss. Zool., Ixiii, 1897, p. 28) prepares a similar 

 vehicle, and adds to it a little solution of corrosive sublimate and a 

 crystal of thymol. 



476. ROBIN'S Carmine Colouring Mass (Traite, p. 33). Rub up 

 3 grms. of carmine with a little water and enough ammonia to 

 dissolve it. Add 50 grms. of glycerin and filter. 



