CHAPTER VIII. 03 



The modus operandi is, on the whole, the same as for other fusion 

 masses, with the difference that the objects are prepared by satura- 

 tion with water instead of alcohol or a clearing agent. After the 

 cooling of the mass it may sometimes be cut at once, but it is 

 generally necessary to harden it. This may be done by treatment 

 for a few minutes with absolute alcohol (KAISER), or for a few days 

 with 90 per cent, alcohol (KLEBS) or chromic acid (KLEBS) or 

 formaldehyde (NICOLAS), or it may be frozen (SOLLAS). 



The mass can be removed from the sections bv means of warm 



V 



water. 



155. Glycerin Gelatin, KLEBS' (Arch. mik. Anat., v, 1869, p. 165).- 

 A concentrated solution of isinglass mixed with half its volume of 

 glycerin. 



KAISER'S (Bot. Centralb., i, 1880, p. 25). One part by weight of 

 gelatin is left for about two hours in 6 parts by weight of water ; 7 parts 

 of glycerin are added, and for every 100 grins, of the mixture 1 grm. of 

 concentrated carbolic acid. The whole is warmed for ten to fifteen 

 minutes, stirring all the while, until the whole of the flakes produced by 

 the carbolic acid have disappeared. 



GERLACH'S (Unters. a. d. Anat. Inst. Erlangen, 1884 ; Journ. Eoy. Mic. 

 Soc., 1885, p. 541). Take gelatin, 40 grms. ; saturated solution of 

 arsenious acid, 200 c.c. ; glycerin, 120 c.c. Clarify with white of egg. 

 The objects to be prepared for imbedding by a bath of one-third glycerin. 



APATHY (Mitth. Z. Stat. Neapel, xii, 1897, p. 718, and Zeit. wiss. 

 Mikr., xxix. 1913, p. 472) soaks small objects first in glycerin and water 

 (equal parts) and then for at least twenty-four hours at 40 C. in a 

 solution of 1 part of gelatin in 3 of glycerin and 6 of water. They are 

 then arranged in some of this in an imbedding box, and the whole is 

 warmed (over calcium chloride) in a stove at 45 to 60 C. until the mass 

 has evaporated down to one-half, losing 5 of its 6 volumes of water (as I 

 understand the description is not clear). Blocks are then cut out 

 and hardened in absolute alcohol (suspended therein) for several days 

 (one' day per millimetre of thickness), cleared in terpinol (one day per 

 millimetre), and cut with a knife wetted with the same. Said to give 

 sections of 3 p., without the least shrinkage. 



BRUNOTTI'S Gold Gelatin Mass (Journ. de Botan., vi, 1892, p. 194). 

 -Twenty grms. gelatin dissolved with heat in 200 c.c. distilled 

 water, and 30 to 40 c.c, of glacial acetic acid with 1 grm. corrosive 

 -sublimate added after filtering. Objects are prepared by soaking 

 in some of the mass diluted with 2 to 3 volumes of water, then 

 imbedded in the undiluted mass. The mass is then hardened in 

 spirit or bichromate of potash, picric acid, or the like. No heat at 

 all is required in this process. 



NICOLAS'S Method (Bibliogr. Anat., Paris, 3 annee, 1896, p. 274).- 

 Preparations are first soaked for one or two day* in a 3 to 



