348 SOME OTHER HISTOLOGICAL METHODS. 



I give it in the form to which it has been brought by the 

 careful study of Schaffer (Zeit. f. wiss. Mik., v, 1, 1888,.p. 17). 

 Sections of bone decalcified with nitric acid (chromic acid 

 may be used, but the stain will be less brilliantly contrasted) 

 are stained for half an hour to one hour in 0*05 per cent, 

 aqueous solution of safranin, washed with water, put for two 

 or three hours in 0*1 per cent, solution of corrosive sublimate, 

 and examined in glycerin. In order to make permanent pre- 

 parations, the sections on removal from the sublimate are 

 rinsed with alcohol, pressed on to a slide with filter paper, 

 cleared for a long time in bergamot oil or clove oil, and 

 mounted in xylol balsam. 



This is a double stain; cartilage, orange; bone, uncoloured 

 .(or green in chromic objects) ; marrow, red. 



BAYERI/S method for ossifying cartilage (Arch. f. milt. Anat., 

 1885, p. 35) is as follows : Portions of ossified cartilage are 

 decalcified in a mixture of equal parts of 1 per cent, hydro- 

 chloric acid and 3 per cent, chromic acid. They are then 

 washed for several days in distilled water, dehydrated, im- 

 bedded in paraffin, and cut. The sections are cleaned with 

 turpentine and soaked in absolute alcohol. They are then 

 stained in MerkePs borax-carmine and indigo-carmine mix- 

 ture ( 230) washed out with absolute alcohol, cleared with 

 clove oil (or, better, with benzin) and mounted in balsam. 

 In order to ensure a somewhat permanent stain the clove oil 

 must be carefully removed with benzin before mounting, as 

 clove oil oxidises the stain, and causes it to fade. For the 

 characters of the stain, see 230. 



MAX FLESCH (Zeit.f. wiss. Mik., 1885, p. 351) particularly 

 recommends this process for the study of the development of 

 dental tissue. 



Blood. 



692. Fixing Agents for Blood Corpuscles. The most recent 

 authors (BiONDi, Mosso, MAX FLESCH) are agreed that by far 

 the most faithful fixing agent for blood corpuscles is osmic 

 acid. A drop or two of blood (Biondi recommends two drops 

 exactly) is mixed with 5 c.c. of osmic acid solution, and 

 allowed to remain in it for from one to twenty-four hours. 

 'I lio exact degree of concentration of the osmium solution is 

 a somewhat important point, and must be made out by expe- 



