and Laboratory Methods. 1-59 



syphilis. In these the marrow was comparatively deficient in lymph cells. With 

 the adult man red marrow was always found in the spongy tissue of the sternum 

 and the bodies of the vertebrae ; and being more easy of access, this was usually 

 the source of material for this investigation. To obtain the marrow fresh, the 

 bones, after being freed from all other tissue, are split lengthwise by a sharp 

 stroke on a strong knife. The lyrnph-cells of the marrow were examined fresh in 

 blood serum, and also after fixation in 70 per cent, alcohol, and staining in picro- 

 carmin, and mounting in glycerin. For nuclear studies, Malassez's method of 

 1882 was used. A slide is laid gently upon the fresh marrow, and the smear is 

 fixed in osmic acid fumes. The results of this method are an improvement on 

 the old smear method, since it avoids tearing and distorting. Such a spot 

 shows three zones ; a central, the largest of considerable thickness not available 

 for study, a peripheral, very thin, of a single layer of cells. This is generally 

 changed by drying slightly. Also, there is a middle zone, thin enough for 

 observation and thick enough to show no effects of drying. Fixation fluids are 

 poured directly upon the slide ; later washing loosens the thick central piece, 

 but the rest remains in place. Besides osmic acid, the author has used Flem- 

 ming's solution, sublimate with platinum-chloride, and Zenker's fluid. Osmic 

 acid, 1 per cent, solution, for 30 to 60 seconds, gave good preparations, but 

 Flemming was still more satisfactory in a strong solution. For staining, the fol- 

 lowing combinations were used : haematein and eosin, haematein and aurantia, 

 hsematein and acid fuchsin, methylen blue and eosin, methylen green and acid 

 fuchsin. The Ehrlich-Biondi-Heidenhain triacid mixture and safranin, with 

 potassium permanganate (1 to 100), as a mordant. According to Henneguy's 

 method, gentian-violet, thionin, and polychromic methylen blue of Unna, were all 

 used. The general method of preparation was as follows : a small spot of 

 marrow is fixed in Flemming's fluid (strong) 10 to 15 minutes, washed out in 

 running water for 15 minutes, bleached in iodin solution (1 to 100.95 per cent, 

 alcohol) for one second, washed in 95 per cent, alcohol to remove the iodin ; 

 wash out in water, stain with a solution of eosin containing glycerin (dry eosin 

 1 part, 95 per cent, alcohol 20 parts, glycerin 50 parts, and water 50 parts) for 

 a long time, so as to over stain. Decolorize in alcohol, and stain the nucleus 

 with the following haematein (haematein 1 part, 95 per cent, alcohol 25 parts, 5 

 per cent, solution of ammonia alum 200 parts) ; wash in water, alcohol, clear in 

 clove oil, and mount in Damar balsam. In such preparations the middle of the 

 spot, as already mentioned, is thick and badly fixed. This is removed with a 

 needle, if it has not already fallen out in the various washings. The cells of the 

 peripheral zone, which have been changed already through drying, show a weakly 

 stained and diffuse nucleus. In the middle zone the cells are well fixed and 

 stained ; red corpuscles are orange, nuclei of lymph-cells violet, protoplasm of 

 these is grey, eosinophil granules are red. Dry preparations, fixed by heat, are 

 useful with reference to histo-chemical reaction, but are useless for nuclear study. 

 By drying its structure is altered ; it stained uniformly and slightly. The changes 

 are similar to those in peripheral zone of spot. The appearance of these altered 

 nuclei explains the definite appearance of normal blood. The diffuse nuclei of 

 certain leucocytes, the large mono-nuclear forms, are brought out by drying. The 

 author has verified his results by sections. The marrow was imbedded in gum 

 or paraffin. a., m. c. 



