VITAMINS 



264 



WALKER'S METHOD 



cc, up to 30 min. Rinse in aq. dest. 

 30 15-min. 3% aq. NajSjOs, 15-30 min. 

 Rinse in aq. dest. 15-30 min. All this 

 in dark room with red light. Change 

 to 70% alcohol and imbed in paraffin. 

 Counterstain with "Kernechtrot" and 

 light green. 



A photometric method for quantita- 

 tive determination of vitamin C in very 

 small amounts of epidermis has been 

 worked out by Carruthers, C, Indust. 

 and Engin. Chem., 1942, 14, 826-828. 



D. According to Sherman (p. 430) there 

 are probably at least 10 such substances 

 having antirachitic potency of which 5 

 are (in 1940) recognized fairly clearly 

 as chemical individuals, D2 and D3 

 being of great importance. Action is 

 measured histologically by the Line 

 Test. 



Di. is molecular compound of D2 and 

 luminsterol which is first product of 

 irradiation of ergosterol with ultra- 

 violet light. 



Dj. Calciferol, C28n440 produced by ir- 

 radiation or ergosterol. 



D3. Antirachitic vitamin. C27H44O, mol. 

 wt. 384.6. This is activated 7-dehydro- 

 cholesterol. 



E. Antisterility vitamin, a Tocopherol, 

 C29H5PO2, mol. wt. 430.4. The 2 other 

 vitamin E factors are /? and 7 tocopherol. 



F. The designation of vitamin F was 

 originally applied to essential fatty acid 

 but it has not been officially accepted. 



G = B2. 



H. This term as Sherman (p. 393) points 

 out has been used in at least 3 ways. 

 It is considered to be Biotin. 



Ki is the first form of the antihemor- 

 rhagic vitamin to be isolated by Dam 

 (see Dam, H., Helv. chim. Acta, 1939, 

 22, 310-313). It is 2 methyl-3-phytyl- 

 1 ,4-naphthoquinone. 



K2 is the second isolated by Doisy, et al. 

 (see Brinkley, S. B., MacCorquodale, 

 D. W., Thayer, S. A. and Doisy, E. A., 

 J. Biol. Chem., 1939, 130, 219-234). 

 It is the same except that there is a 

 longer more unsaturated side chain. 

 Neither of the two can be localized 

 histologically but we may expect histo- 

 logical studies of their action. 



M. An unknown factor said to be essential 

 to the nutrition of monkeys (Day, P. L., 

 et al., J. Exp. Med., 1940, 72, 463-^77). 



P. Permeability vitamin, citrin, said to 

 be essential for maintenance of walls of 

 small blood vessels. For a discussion 

 of vitamin P as measured by capillary 

 fragility see Rapaport, H. G., and Klein, 

 S., J. Pediatr., 1941, 18, 321-327. 

 Volkonsky Method for mitochondria. This 

 is a complicated technique involving 

 staining with anilin fuchsin, aurantia, 

 methylene violet and azure II but can 



give splendid results. See original ac- 

 count (Volkonsky, M., Bull, d'hist. 

 Appl., 1928,5, 220-222). 

 Volume. As explained by Danielli (Bourne, 

 p. 39), cell volume is a function of the 

 number of contained osmotically active 

 particles unless change is restricted by 

 rigidity of the enveloping membrane. A 

 satisfactory technique for measuring the 

 volume of red blood cells is to determine 

 photoelectrically light absorption of a 

 suspension (Jacobs, M. H., Biol. Bull., 

 1930, 58, 104). The simplest way to 

 obtain ratio for cytoplasmic and nuclear 

 volumes is to outline nuclei and cyto- 

 plasms on kodaloid and determine the 

 weights as has been recently done in 

 carcinogenesis (Cowdry, E. V. and 

 Paletta, F. X., J. Nat. Cancer Inst., 

 1941, 1, 745-759). The technique, of 

 course, varies with structure involved, 

 for example thyroid colloid (Stein, H. 

 B., Am. J. Anat., 1940, 66, 197-211), 

 fresh endocrine glands (Swinvard, C. 

 A., Anat., Rec, 1939, 74, 71-78). To 

 determine volume and cell numbers in 

 small organs (Dornfeld, E. J., et al., 

 Anat. Rec, 1942, 82, 255-259). For 

 influence on tissue volume of various 

 methods of fixation, dehydration and 

 imbedding, see Stowell, R. E., Stain 

 Techn., 1941, 16, 67-83. 

 Volume measurements 



1 liter = 2.1 U. S. pints (1.76 Imperial 

 pints) 



1 cc. = 16? minims (17 minims B.P.) 



1 gallon = 3.79 liters (1 Imperial gallon = 

 3.79 liters) 



1 pint = 473 cc. (1 Imperial pint = 568 cc.) 



1 fluid ounce = 29.5 cc. (1 fluid ounce 

 B.P. = 28.4 cc.) 



1 fluid drachm = 3.7 cc. (1 fluid drachm 

 B.P. = 3.5 cc.) 



1 minim = 0.065 cc. 

 Volutin. Spherical bodies in fungi, bacteria 

 and other organisms (Taylor in Mc- 

 Clung's Microscopical Technique, p. 

 221). According to R. F. MacLennan, 

 in Calkins, G. N. and Summers, F. M., 

 Protozoa in Biological Research. New 

 York: Columbia University Press. 

 1941, 1148 pp., the term "volutin should 

 either be dropped or definitely re- 

 stricted to metachromatic granules 

 which respond to Feulgen's stain when 

 used without hydrolysis." 

 Von Kossa, see Calcium. 

 Vulpian Reaction named after a Parisian 

 physician. Fresh slices of the adrenal 

 immersed in dil. aq. ferric chloride show 

 a green coloration of the chromaffin cells 

 of the medulla. It is a test for tissues 

 producing epinephrine. See : chromaffin 

 reaction and osmic acid. 

 Walker's Method for intestinal protozoa is 

 recommended as an excellent rapid 



