252 SUMMARY OF CURRENT RESEARCHES RELATING TO 



For staining the blood-film, sock-methylen-blue and eosin are ex- 

 clusively used. The author uses both solutions, freely diluted, with- 

 out subsequent differentiation and 1 p.c. solutions of soda-methylen-blue 

 and eosin followed by differentiation. The former procedure gives good 

 results for clinical observations, while the latter is more advantageous 

 for the study of nuclear changes. 



For the first method the stock solutions consist of (1) 0*1 p.c. eosin 

 solution; (2) 1 p.c. inethylen-blue solution, to every 100 ccm. of which 

 are added 6 ccm. of 5 p.c. soda solution ; the mixture is then inoculated 

 for 48 hours at 55°-60° C. The eosin solution may be added immediately 

 after removal of the metbylen-blue solution from the incubator or at any 

 subsequent period. When required for staining films 3 ccm. of the 

 methylen-blue solution are diluted with 42 ccm. of distilled water and 

 5 ccm. of the eosin solution with 25 ccm. of distilled water. The eosin 

 is poured slowly into the methylen-blue solution, and the mixture kept 

 stirred the while. The time required for staining is about 15 minutes. 

 On removal the preparations are washed with water, dried with blotting- 

 paper, and mounted in balsam. 



In the second method or that followed by differentiation, the methylen- 

 blue solution is the same, but the eosin is a 1 p.c. and they are mixed 

 in the proportion of 5 of the former to 2 of the latter. The staining 

 takes from 3-5 minutes. The overstained films are decolorised and 

 differentiated with the following solution : — 120 ccm. of 95 p.c. alcohol, 

 4-5 drops of acetic acid, and 2 ccm. of aqueous 1 p.c. eosin solution. 

 The time required for differentiating is from 5-15 seconds. The pre- 

 parations are then washed with water for 1—2 minutes, and having been 

 dried in the usual way, are mounted in balsam. Judging the right 

 moment to cease differentiating requires a little practice and experience. 

 The coloured illustrations are extremely effective. 



Examining 1 Blood-plates. — Dr. Deetjen * used films of agar, to 

 which were added small quantities of sodium chloride, metaphosphate 

 of soda, and potassium biphosphate. Some blood from the ringer was 

 placed on the agar film, and the preparation examined at once, or after 

 fixation with osmic acid and staining with hasmatoxylin-eosin. By this 

 method it was shown that blood-plates of mammalian blood are nucleated 

 masses of protoplasm, exhibiting amoeboid movements. 



H. Hirschfeldf fixed blood-films by heat at 110° for 5-30 minutes, 

 and afterwards stained them with eosin-methylen-blue, and also with 

 Dilafield's haematoxylin. By this method it was demonstrated that 

 blood-plates originated from red corpuscles. 



M. C. Dekhuyzen J employed the following methods for examining 

 thrombocytes or blood-plates. For the study of living blood-cells he 

 used physiological salt solutions which were, as far as possible, isotonic 

 with the blood itself, about 0*8 p.c. 



For permanent preparations a mixture of osmic and acetic acids and 

 methylen-blue was used for fixing and staining. This mixture (osmacet) 



* Virchow's Archiv, clxiv. (1901) pp. 239-63 (1 pi.). 

 t Tom. oii., pp. 195-211 (1 pi.). 



X Anat. Anzeig., xix. (1901) pp. 529-40. See Zeitschr. wiss. Mikr., xviii. (1902) 

 pp. 539-41. 



