CHAPTER XXII. 



INJECTIONS OTHER MASSKS (COLD) . 



501. FOL'S Metagelatin Vehicle (Lehrl., p. 17). If a slight 

 proportion of ammonia be added to a solution of gelatin, and 

 the solution be heated for several hours, the solution passes 

 into the state of metagelatin, that is, a state in which it no 

 longer coagulates on cooling and can be injected without 

 warming. Colouring masses may be added to this vehicle, 

 which may also be thinned by the addition of weak alcohol. 

 After injection the preparations are thrown into strong 

 alcohol or chromic acid, which sets the mass. 



According to the Encycl. mik. Technik., metagelatin is 

 usually prepared by warming with concentrated acetic or 

 oxalic acid. It may be neutralised afterwards with car- 

 bonate of lime. 



502, TANDLER'S Gold Gelatin Mass (Zeit. rnss. mik., xviii, 

 1901, p. 22). Five grins, of gelatin are soaked in 100 c.c. 

 of water, warmed and melted, and combined with Berlin 

 blue. Then 5 to 6 grms. of iodide of potassium are slowly 

 incorporated. The mass generally remains liquid enough for 

 injection down to a temperature of 17 C., but if it should 

 coagulate a little more iodide should be added. After 

 injection you may fix with 5 per cent, formed. The speci- 

 mens will bear decalcification with hydrochloric or sul- 

 phurous acid. 



PEARL (Journ. Appl. Micr., v, 1902, p. 1736) takes 8 to 10 

 per cent, of the iodide. 



MAYER (Grundzuge LEE and MAYER, 1910, p. 250) takes 

 simply 10 grms. gelatin, 10 grms. hydrate of chloral and 100 c.c. 

 water. 



MOZEJKO (Zeit. wins. Mik., xxvii, 1910, p. 374), finds that 



