ROBIN'S GLYCERIN-GELATIN VEHICLE. 259 



CHAPTER XXI. 



INJECTIONS GELATIN MASSES. 



457. Introduction. Injection masses are composed of a 

 coloured substance, technically termed the colouring mass, and 

 of a substance with which that is combined, technically termed 

 the vehicle. 



The following formulae are grouped according to the nature 

 of the vehicle. A note on the employment of nitrite of amyl 

 for provoking the dilatation of vessels will be found at 500. 



458. Robin's Gelatin Vehicle (Traite, p. 30). Take some 

 gelatin, of the sort known as " colle de Paris." (This 

 gelatin is found in commerce in the form of thin sheets, 

 marked with lozenge-shaped impressions of the cords which 

 supported them whilst drying.) Soak it in cold water, then 

 heat in water over a water-bath. One part of gelatin should 

 be taken for every 7, 8, 9, or even 10 parts of water ; it is a 

 common error to employ solutions containing too much gelatin. 

 The solution is now to be combined with one of the colouring 

 masses given below. 



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 added to the mass will preserve it (HOYER). 

 A sufficient dose, at least 2 per cent., should be employed (see 

 below, 472, 473). 



459. Robin's Glycerin-Gelatin Vehicle (Traite, p. 32).- Dis- 

 solve in a water-bath 50 grms. of French gelatin (" colle de 

 Paris") in 300 grms. of water in which has been dissolved 

 some arsenious acid; add of glycerin 150 grms., and of car- 

 bolic acid a few drops. Unlike the pure gelatin vehicles, this 

 mass does keep indefinitely. 



The colouring masses recommended for combination with 

 the vehicles above described are made as follows : 



