SULPHUR 



235 



SURFACE MEASUREMENTS 



found in living things except in the 

 thiobacteria. Histochemically one has 

 to consider sulphates and masked sul- 

 phur. Macallum has devised a method 

 for sulphates but Lison (p. 121) says 

 that it only gives very rough localization 

 in tissues because the salt is diffusible. 

 For organic, masked sulphur see Sulf- 

 methemoglobin, Glutathione, Radio- 

 sulphur. 



Sulphurous Acid. This is used for rinsing 

 sections which have been stained with 

 Feulgen or Schiff's reagent. Prepare 

 by dissolving 1 gm. potassium or sodium 

 meta bisulphite in 200 cc. of tap water 

 to which 10 cc. of N HCl are added. 



Sultan Red 4B, see Benzopurpurin 4B. 



Sun Yellow (CI, 620), a direct stilbene dye, 

 light fastness 3. Serves as a mordant 

 to produce green in combinations with 

 blue counterstains. Many combina- 

 tions of Sun Yellow with blue and red 

 dyes in double, triple and quadruple 

 stains are described (Emig, p. 44-45). 



Superchrome Black PV (CI, 170) of NAC, 

 an acid monoazo mordant dye action of 

 which on plant sections and blue green 

 algae is described (Emig, p. 34). 



Superchrome Violet B (CI, 169) of NAC, an 

 acid monoazo mordant dye of light fast- 

 ness 3 of which action on blue green 

 algae is described (Emig, p. 34). 



Superchrome Garnet Y (CI, 168) of NAC, an 

 acid monoazo mordant dye of light fast- 

 ness 3 of which action on blue green 

 algae is described (Emig, p. 34). 



Supravital Staining. By this is meant 

 staining upon the living state. In other 

 words stains are applied to cells re- 

 moved from a living animal, or to cells 

 within a recently killed animal. Thus 

 blood cells are removed from the body 

 and, while still living, are stained supra- 

 vitally or the stains are applied to still 

 living cells of, say, the stomach within 

 the body of a recently killed animal by 

 vascular injection. The essential point 

 is that the stains act upon living cells 

 but the cells do not go on living, neither 

 does an animal injected intra vascularly 

 with a supravital stain. Janus green 

 is our most useful supravital stain. 

 Cells supravitally stained by it die and 

 when it is injected in sufficient quantity 

 into a living animal, the animal dies 

 likewise for it is toxic. Vital stains, 

 on the contrary, do not kill cells and can 

 be safely injected into living animals 

 since they are nontoxic in the concen- 

 trations necessary to obtain the desired 

 results. This kind of staining used to 

 be called intravital in contrast to supra- 

 vital. See Vital Stains. 



Supravital stains have been known 

 for a long time but their introduction as 

 essential means of investigation is due 



primarily to Professor R. R. Bensleyof 

 the University of Chicago (Am. J. Anat., 

 1911, 12, 297-388). He showed their 

 usefulness in demonstrating specifically 

 by vascular injection the different epi- 

 thelial components of the pancreas and 

 he called attention to the fact that to 

 stain mitochondria specifically it is 

 essential to use janus green having the 

 composition of diethylsa.ha,nm-azodi- 

 methylanilin, that the dimethyl com- 

 pound will not work. The supravital 

 staining of blood cells began with the 

 demonstration by Cowdry at Hopkins 

 (Internat. Monatschr. f. Anat. u. 

 Physiol., 1914, 31, 267-286), that this 

 particular janus green B as used in Ben- 

 sley's laboratory stains the mitochon- 

 dria in human white blood cells specifi- 

 cally. The method was later further 

 developed by Sabin and her associates. 

 Details of techniques are given under 

 janus green, neutral red, brilliant cresyl 

 blue, pyronin, methylene blue, naph- 

 thol blue and cyanamin. Useful table 

 giving reactions of types of blood cells 

 (Gall, E. A., J. Lab. & Clin. Med., 

 1934-35, 20, 1276-1293). 

 Suramin, a drug purchasable under term 

 of Naphuride (Winthrop), is only a 

 feeble inhibitor of growth of lympho- 

 sarcoma transplants. Its cytotoxic 

 effect is rather similar to that of colchi- 

 cine on lymphoid tumors (Williams, 

 W. L., Cancer Research, 1946, 6, 344- 

 353). 

 Surface Measurements. To determine the 

 surface area of structures of microscopic 

 size involves many techniques some of 

 which are rather complicated. The 

 following references are given to methods 

 and results in a wide variety of in- 

 stances. Perhaps the particular surface 

 to be measured will be sufficiently simi- 

 lar to one of these to justify employ- 

 ment of the same technique or a modi- 

 fication of it. 



Endothelium of vascular capillaries — 

 6300 sq. meters — Krogh, A., Anatomy 

 and Physiology of Capillaries, Yale 

 Press, 1929, 422 pp. 



Erythrocytes combined — 3500 sq. me- 

 ters — Evans, C. L., Recent Advances in 

 Physiology. Philadelphia: Blakiston, 

 1926, 383 pp. 



Filtration surface of both kidneys 

 combined — 1.56 sq. meters — Vimtrup, 

 B. J., Am. J. Anat., 1928, 41, 132-151. 

 See also recent measurements for al- 

 bino rat by Kirkman, H. and Stowell, 

 R. E., Anat. Rec, 1942, 82, 373-389. 



Gastric glands secreting surface — 

 2.7 sq. meters — Scott, G. H. (personal 

 communication), see Cowdry 's Histol- 

 ogy (p. 282). 



Lacteal surface in small intestine — 



