SMEARS 



227 



SOLID GREEN JJO 



along the surface of the first slide. The 

 angle at which the pusher is held plus 

 the speed of smearing and the amount 

 of blood will determine the thickness of 

 the film. Ordinarily it should be so 

 thin that the reds are smeared in a single 

 layer. But for certain purposes as in 

 the search for some parasites thick 

 smears are the best (see Blood Smears). 



In the case of cells in cerebrospinal 

 and other fluids and of some bacteria 

 and parasites it may be desirable to 

 concentrate the objects by centrifuga- 

 tion because otherwise smears would 

 show too few of them. See Concentra- 

 tion Methods. The precautions de- 

 tailed above to obtain evenness are sel- 

 dom required. The material simply is 

 transferred to the slide in a platinum 

 loop or glass pipette and spread on it. 

 Smears of lymph nodes and spleen are 

 generally made by drawing "streaking" 

 the freshly cut, moist surfaces along 

 slides. Impression preparations of 

 these tissues are not smears but they 

 serve the same purpose. In making 

 them the surface of slide is quickly 

 pressed against the surface of the tissue 

 and a considerable number of the easily 

 detachable cells adhere to the slide 

 where they are quickly dried, or, while 

 still wet the impression can be fixed in 

 Helly's fluid (i.e. formalin Zenker) as 

 advised by Maximow (see Downey, p. 

 2001). McClung (p. 262) recommends 

 smears on cover glasses for certain germ 

 cells. 



The smears can be fixed by gentle 

 heat, or by methyl alcohol or in special 

 cases in formalin or osmic vapor. Giem- 

 sa's stain is the most popular but a 

 great many others are available es- 

 pecially for Bacteria. 



Smears cannot be made of fixed cells 

 isolated by Maceration in the same way 

 because they are not present in body 

 fluids which when they dry facilitate 

 sticking of the cells to the slides. It is 

 therefore necessary to spread them on 

 slides previously moistened with a very 

 small amount of Albumen-Glycerin 

 before drying. 

 Smith-Dietrich method for lipoids (Die- 

 trich, A., Verh. d. Deut. Path. Ges., 

 1910, 14, 263-268). Treat frozen sec- 

 tions of formalin fixed tissues 1-3 days 

 in 5% aq. potassium bichromate at 37°C. 

 After washing in aq. dest. stain 4-5 hrs. 

 in Kultschitzky's hematoxylin (stock 

 solution 10% in abs. ale. ripened at 

 least 6 months, 10 cc. + 2% acetic acid, 

 90 cc). Wash. Differentiate over 

 night in Weigert's borax ferricyanide 

 (borax, 2 gm.; potassium ferricyanide, 

 2.5 gm. ; aq. dest., 100 cc). Wash care- 

 fully. Mount in syrup of levulose. 

 Lipoids dark blue. Lison (204) consid- 

 ers the positive staining as characteris- 



tic for a lipine (lipoid) if the possible 

 presence of cholesterides and cholesterol 

 is excluded. 



Smooth Muscle, see Contraction Bands. 



Soap- Wax technique for paraffin imbedding, 

 see Lebowich. 



Soaps. Sodium and potassium salts of fatty 

 acids, see Fischler's modification of 

 Benda method. 



Sodium. A method for the retention of 

 sodium and potassium in microinciner- 

 ated tissue has been proposed by Poli- 

 card, A., and Fillet, D., Bull. d'Hist. 

 Appl., 1926, 230-235. In their opinion 

 these two elements are present as chlor- 

 ides in the tissue and their conversion 

 to sulphates by treating the sections 

 with sulphuric anhydride fumes makes 

 them more stable and better able to 

 withstand the high temperature of in- 

 cineration. See Microincineration, Ra- 

 dios odium. 



An ultramicromethod for sodium 

 employing the polarograph has been 

 devised by Carruthers, C., Indust. and 

 Engin. Chem., 1943, 15, 70-71. It has 

 been used for analysis of small amounts 

 of epidermis by Suntzeff, V. and Car- 

 ruthers, C., Cancer Research, 1943, 3, 

 431-433. If it is only necessary to 

 prove presence or absence of traces of 

 sodium try Histospectrography. 



Sodium Alizarin Sulphonate. See Hydrogen 

 Ion Indicators. 



Sodium Fluoride effect on teeth (Cowdry's 

 Histology, p. 267). 



Sodium Paradipicrylamine, see Siena Or- 

 ange. 



Soil. Bacteria. 1. Conn's Rose Bengal 

 method (McClung, p. 146). To 1 gm. 

 soil add gelatin fixative (0.015% gelatin 

 in boiling water used after it has cooled) 

 to make 10 cc. Place about 0.01 cc. on 

 slide to cover 1 sq. cm. Dry on boiling 

 water bath. Stain with Rose bengal as 

 for Slime Bacteria. Unless counts are 

 to be made the amount smeared on the 

 slide is not important. 



2. Fast acid blue (C.I. 760) is 

 strongly recommended (Romell, L. G., 

 Stain Techn., 1934, 9, 141-145) but it is 

 doubtful whether any manufacturer 

 other than I. G. Garbenindustrie makes 

 the dye. According to the General 

 Dyestuffs Corporation it is contained in 

 violamin 3B. Dry suspension of soil 

 on slide which has been fixed in alcohol 

 with 0.05% dye in 4% aq. phenol. 

 Washing is unnecessary. Examine 

 smears in water. Details are given by 

 Romell. 



Solanylin, a dye extracted from the egg- 

 plant (Solanum melongena, var. escu- 

 lenta) proposed as a substitute for 

 hematoxylin. It will stain nuclei and 

 mucus (Fuse and Suzuki, Arb. Anat. 

 Inst, zu Sendai, 1935, 17, 175-181). 



Solid Green JJO, see Brilliant Green. 



