SURAMIN 



331 



SURFACE TENSION 



(Internat. Monatschr. f. Anat. u. 

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

 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). A critique of 

 supravital staining of blood cells is 

 provided by Schwind, J. L., Blood, 

 1950, 5, 597-622. 

 Suramin, a drug purchasable under term 

 of Naphuride (Winthrop), is only a 

 feeble inhibitor of growth of lympho- 

 sarcoma transplants. Its cytotoxic 

 efTect is rather similar to that of colchi- 

 cine on lymphoid tumors (Williams, 

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

 353). 

 Surface Films, study of by micrurgical 

 technique, Chambers, R. W. and Kopac, 

 M. J. on McClung's Microscopical 

 Technique, 1950, p. 542. 

 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 intestme-;- 

 5 sq. meters — Policard, A., Pr6cis 

 d'Histologie Physiologique. Collection 

 Testut, Paris: G. Doin, 923 pp., after 

 Potter. 



Large intestinal crypts — 4.2 meters — 

 Policard, ibid. 



Mitochondrial, zymogenic and nuclear 



surfaces in pancreatic acinous cells of 

 guinea pig — duNouy, P. L. and Cowdry, 

 E. v., Anat. Rec, 1927, 34, 313-329. 



Respiratory surface plus nonrespira- 

 tory epithelial surface of airways of 

 lungs — 70 sq. meters — Wilson, H. G., 

 Am. J. Anat., 1922, 30, 267-295. 



Surface Replica Method, see Shadow Cast- 

 ing in Electron Microscopy. 



Surface Tension. This, or more correctly 

 interfacial tension, is tension at the 

 surface of a fluid tending to produce 

 a sphere. Surface tension is high for 

 water and low for alcohol. Soap de- 

 creases surface tension of water because 

 it concentrates at surfaces. Bile acids 

 lower surface tension of blood serum. 

 According to Gibbs any substance 

 lowering interfacial tension will con- 

 centrate at the interfaces. Surface 

 tension is best determined by a Cenco- 

 du Nouy tensiometer capable of meas- 

 uring the force required in lifting a 

 standard platinum ring out of the 

 surface of the liquid. The ring must 

 obviously be held absolutely horizontal 

 and be pulled away slowly (Holmes, 

 H. N., Glasser's Medical Physics, 257- 

 263). 



Much has been written about surface 

 tension (Reviews: Harvey, E. N., and 

 Danielli, J. F., Biol. Rev., 1938, 13, 

 319-341 and Danielli, J. F. in Bourne, 

 pp. 69-98). Before measurements can 

 be made on cells it is obviously neces- 

 sary to isolate them and this entails 

 risk of injury which is much greater 

 in the case of mammalian cells than of 

 the sea urchin eggs usually employed. 

 The following techniques are given as 

 examples : 



1. By centrifuging marine eggs elon- 

 gation can be produced and, when the 

 length exceeds a certain ratio of diam- 

 eter, the egg divides. Knowing the 

 minimum force required, the difference 

 in density between the 2 halves and the 

 circumference of the cylinder, it is 

 apparently possible to calculate the 

 tension at the surface (Harvey, E. N., 

 J. Franklin Inst., 1932, 214, 1-23). 



2. By compressing sea urchin eggs 

 by a minute gold beam the internal pres- 

 sure can be calculated and from this the 

 surface tension (Cole, K. S., J. Cell & 

 Comp. Physiol., 1932, I, 1-9). 



3. By stretching a cell between the 

 two needles of a microdissection ap- 

 paratus the force required to secure a 

 given degree of elongation can be deter- 

 mined and thence the surface tension 

 (Norris, C. H., J. Cell & Comp. Physiol., 

 1939, 14, 117-133). 



4. Surface tension is probably to 

 some extent at least conditioned by the 

 elasticity of the superficial plasma gel 



