258 CHAPTER xxr. 



masses — glycerin masses especially — stimulate the contraction 

 of the 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 ansesthetised with a mix- 

 ture 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 Saegent, in St. Louis Med. Journ., 

 1886, p. 207; and Journ. Roy. Mic. 8oc., 1887, p. 341). 



Or, morphia may be added to the injection mass, or one 

 per cent, of lactic acid. Mozejeo {Zeit. wiss. mik., xvi, 1909, 

 p. 545) prefers a saturated solution of 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. 



Kobin's Masses. 



482. Robin's Gelatin Vehicle [Traite, -p. 30). — One part of 

 gelatin soaked and melted in 7, 8, 9, or even 10 pai'ts 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. 



483. Robin's Glycerin-gelatin Vehicle [Traite, p. 32). — Dis- 

 solve in a water-bath 50 grms. of gelatin in 300 grms. of 

 water, in which has been dissolved some arsenious acid ; add 

 of glycerine 150 grms., and of carbolic acid a few drops. 

 Unlike the pure gelatin vehicles, this mass does keep in- 

 definitely. 



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

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

 crystal of thymol. 



484. 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. 



