98 GELATIN METHOD 



is added to the section and the coverslip is put in place. After 

 a few hours, the sHp will be firmly fixed to the slide. Directions 

 for making glychrogel are given in § 474. 



180. Other 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 grm. 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. Roy. Mic. 

 Soc, 1885, p. 541). Take gelatin, 40 grm. ; 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 volimies of water (as we 

 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 /i, without the least shrinkage. 



Brunotti's Cold Gelatin Mass {Journ. de Botan., vi, 1802, 

 p. 194). Twenty grm. 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 of 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 days in a 

 3 to 4 per cent, aqueous solution of gelatin kept at 25° C, then 

 for the same time in a 10 per cent, solution, and then for two or 

 three days more in a 20 to 25 per cent, solution containing 8 to 

 10 per cent, of glycerin and kept at 35° C. They are then 

 imbedded in some of the same mass in paper trays, and as soon as 

 the gelatin has set are thrown into a mixture of formol 1 part, 

 water 7. After a few days therein the gelatin has become hard 

 and insoluble, and may be cut or preserved for months in weak 

 formol solution, or dilute alcohol or glycerin, or even in pure 

 water. Sections must be very gradually passed through successive 

 alcohols for dehydration, as they curl up very easily. They 

 however, flatten out at once on being brought from absolute 



