1178 Journal of Applied Microscopy 



formalin mixture needs to be kept in the dark, and a dark glass dropper was 

 used. About equal parts of the two liquids were taken. A Thoma-Zeiss pipette 

 was filled with blood to 0.5 mark, and filled to 1.20 with the mixture ; 1.10 does 

 not completely destroy the red cells. After five minutes, the chamber is filled 

 from the pipette, and the white cells are allowed to settle. Then the blood plates 

 are found to be arranged in characteristic masses, and stain a light gray-blue ; the 

 erythrocytes are destroyed ; nucleated red cells are sometimes recognizable by 

 their greenish " discoplasm." Malaria plasmodia stain blue, but their recognition 

 is uncertain. Leucocytes are stained as to both nuclei and granules. Eosino- 

 phil granules are clearly outlined, and the nuclei remain bright. Neutrophil 

 granules are gray-violet. Most cell granules are unstained. The mononuclear 

 or ungranulated, leucocytes of normal blood are homogenous, with faintly blue 

 cytoplasm and varying nuclei. Nuclei of the larger lymphocytes are clearer, and 

 light violet, the others bright blue and oval. The nuclei of granulated leucocytes 

 stain lightly. The granulated mononuclear, or "Mark" cells, are conspicuous 

 by their size and varying form of nuclei. These are principally recognized by 

 their granules and the size of the nucleus. For a counting chamber, Elzholz's 

 (Reichert) was used. This has a capacity of 0.9 cubic miUimeter. The blood 

 is diluted twenty times, and the whole field is counted. The contained number 

 is multiplied by ^^^ or 22.222. Many cover-glass stained preparations were also 

 studied. Preparations were stained for a few minutes in eosin, and for half a 

 minute in methylen blue diluted five times with water. Careful fixation is neces- 

 sary for good results in staining; heating in a hot chamber at 115° for an hour, 

 or for a few minutes at 120 — 125°, gives good results for both red and white 

 cells. The triacid stain was used when it was desired to stain the neutrophil 

 granules. The mixtures given above afford excellent results not only on blood 

 but also on sputum, pus, and other secretions. a. m. c. 



Lewinson, J. Zur Methode der Fettfiirbung Osmic acid is the usual fixation and 

 Zeitschr. f. wiss. Mikros. u. f. Mikr. Tech. ^ . . n • ^ r r ^ ^ ^ ■ , ^ 



17: 321-326 iQoo. stammg fluid for fats, but it has several 



disadvantages. It is expensive, it fixes 

 but a small part of the tissue put into it or any of the liquids in which it is an 

 active agent. Any fat near the middle of the tissue remains unfixed and un- 

 stained. The stain of osmic acid is very often of short duration, and it is almost 

 impossible to use other stains after this fixative. Experimenting on myelinic 

 fibers, a haematoxylin method of Wolters' was used. By modifications it was 

 found that other tissues than myelinic fibers took this stain. The author 

 tried concentrated nuclear stain, warmed, after definite fixation methods, 

 to see if any result in staining fat could be obtained. A concentrated solution 

 of methylen blue in 2 to 5 per cent, salt solution, and haematoxylin in acetic acid, 

 were first tried on objects fixed in different fluids. Celloidin sections of the 

 ovary of a rabbit fixed in picric acid were stained in such a warmed solution of 

 methylen blue as described above for 10 to 15 minutes. After decolorizing with 

 weak aqueous hydrochloric acid and counterstaining with alcoholic picric acid, 

 the following results : Nuclei of the cells are blue, protoplasm yellow-green, and 

 the connective tissue is violet. The fat in the follicles takes the form of small, 

 dark, almost black fat-corpuscles. For a modification of Wolters' method the 



