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mark the principal stages in the development of knowledge regarding the nonascosporogenous and filamentous yeasts called "monilias." During the past years several new papers have been published. They may be classified in two groups in accordance with the procedures used for the identification of the species within the genus Candida. Martin et al. (1937) and Martin and Jones (1940) adopted the method summarized by Conant (1940), whose procedures are as follows: (a) appearance of the growth in Sabouraud's glucose broth, on Sabouraud's glucose agar, and on beef-extract blood agar plates at pH 7.4 is studied; (b) the microscopical details are studied on corn meal agar slide cultures; (c) the fermentation reactions are tested in beef extract broth with glucose, maltose, sucrose, and lactose, in tubes sealed wTith sterile vaseline, and incubated at 37 C for 10 days. Conant recognized 7 species, M1onilia albicans, M. parakrusei, Ml. krusei, 3i. tropicalis, M. pseudotropicalis, M. stellatoidea, and M. guilliermondi. On the other hand, Langeron and Guerra (1938) adopted more complex methods in accordance with the procedures that Stelling-Dekker (1931) and Lodder (1934) used for the study of the ascosporogenous and nonascosporogenous yeasts. They studied the appearance of the growth on Sabouraud's agar, in 2 per cent glucose, 1 per cent peptone broth, and in Raulin's medium; the morphology was studied on slide cultures. T'he study of the biological characteristics included: (a) fermentation reactions with glucose, sucrose, lactose, maltose, fructose, galactose, and raffinose in tubes sealed with paraffin; (b) the study of the assimilation of these carbohydrates and of nitrogen (peptone, ammonium sulphate, asparagine, urea, histidine, glycocoll, potassium nitrate, and sometimes tryptophane); (c) utilization of ethyl alcohol; (d) growth in milk; (e) liquefaction of gelatin. Langeron and Guerra accepted 16 species which include those accepted by the American authors except MIonilia stellatoidea, which they did not study. Conant does not admit as valid some species admitted by Langeron and Guerra: Candida triadis and C. aldoi of the classification of Langeron and Guerra are considered by Conant as synonyms oL Candida (Monilia) albicans; Candida intermedia as identical with Candida tropicalis; Candida brumpti, Candida chalmersi, and Candida flareri as synonyms of Candida parakrusei. Diddens and Lodder (1939a) recognized the genera Candida Berkhout and 317

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In 1942, the senior author reported that a strain of Streptomyces (Actynomyces) albus stimulated the growth of a strain of Trichophyton discoides Sabouraud, common cause of tinea in calves and children in Uruguay, on a glucose peptone agar. He also found that the addition of thiamine to the medium had the same effect. The ability of Streptomyces albus to synthesize thiamine was proved by the growth of Phycomyces blakesleeanus. Later on, Robbins, Mackinnon, and Ma (1942) reported that Mackinnon's strain of Trichophyton discoides had a ccmplete deficiency for pyridoxine, DLinositol, and molecular thiamine. In addition, there were partial deficiencies for unidentified substances present in pEptcne, casein hydrolyzate, hydrolyzed egg albumen, malt extract, gelatin, and a filtrate prepared frem white potatoes. These partial deficiencies could not be Eatisfied by biotin, riboflavin, folic acid, pimelic acid, para-aminobenzoic acid, pantothenic acid, hypoxanthine, guanine, nicotinamide, 2-methyl-1-1.4-naphthoquinone diacetate, seven pyrimidine and purine bases, and 43 amino acids. After our studies with strain 688, which we identified as T. discoides, we thought that vitamin deficiencies might be useful for the identification of species; that is, that strains of the same species would show the same deficiencies. Trying to elucidate this interesting problem we cultivated 5 strains of T. discoides and 2 strains of T. ochraceum on synthetic media with pyridoxine, thiamine, and DL-inositol, alone and in all possible combinations. EXPERIMENTAL STUDY Materials and methods. The organisms were cultivated at 30 C on agar slopes in neutral glass test tubes, 20 by 150 mm. Each tube contained 8 ml of a basal medium composed, per liter, of 50 g glucose, 2.0 g purified asparagine, 0.5 g MgSO4c7H2O, 1.5 g KH2PO4, and 15 g purified agar. To this medium 0.1 ml of the following solution of mineral supplements was added: 5.7 mg H3BO3, 18.6 mg CuSO4'5H20, 173 mg (NH4)2Fe2(SO4)4-24H20, 7.1 mg MnCl2-4H20, 3.6 mg ammonium molybdate (85 per cent), 79 mg ZnSO4c7H20, and 100 ml redistilled water. This medium was autoclaved for 20 minutes at 115 C. The growth factors were added before solidification of the medium in the dose of 5 millimicromoles of thiamine, 5 millimicromoles of pyridoxine, and 1 mg of DL-inositol, singly and in all possible combinations. At the same time tubes were prepared containing the basal medium plus 0.1 g peptone (Difco) and 5 millimicromoles of thiamine. To another series of tubes nothing was added (basal medium).

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