CHAPTER XXII. 



INJECTIONS OTHER MASSES (COLD). 



492. FOL'S Metagelatin Vehicle (Lehrb., p. 17). If a slight pro- 

 portion 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 carbonate of lime. 



493. TANDLER'S Gold Gelatin Mass (Zeit. wiss. Mik., xviii, 1901, 

 p. 22). Five grms. 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, formol. The specimens 

 will bear decalcification with hydrochloric or sulphurous acid. 



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

 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. wiss. Mik., xxvii, 1910, p. 374) finds that 10 per 

 cent, (or more) of sodium salicylate will retard the setting of gelatin 

 for hours at normal temperatures. 



Any of these masses may be made to set in the tissues by means of 

 weak formol. 



Glycerin Masses. 



494. BEALE'S Carmine Glycerin Mass (How to Work, etc., p. 95). 

 Five grains of carmine are dissolved in a little water with about 

 5 drops of ammonia, and added to half an ounce of glycerin. Then 

 add half an ounce of glycerin with 8 or 10 drops of acetic or hydro- 

 chloric acid, gradually, with agitation. Test with blue litmus 



