96 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS in dandruff scales and associated it with this condition although with- out determining its etiologic rela- tionship. Moore and his associates, ß however, g,•ing reC:)ent mycologic have been able to estab- technique lish Pityrosporum ovale as a causa- tive agency:of infectious dandruff. Most important of all, of course, are the results obtained by Moore and his associates and Durfee and Cousins. They have proved, by applying Koch's postulates, that Pityrosporum ovale is a causative agent of infectious dandruff. This is true because it has been proved that: 1. P. ovale is present in every case of infectious dandruff. 2. P. ovale has been isolated from infectious dandruff and grown in pure culture. 3. P. ovale, in pure culture, when inoculated into the skin of rabbits and the scalp of hu- mans, gave rise to infectious dandruff. 4. P. ovale was observed in and recovered from experimen- tally produced infectious dan- druff. This is sound evidence of the etiological relationship between Pity- rosporum ovale and infectious dan- druff. It is clear from the above evidence that a micro6rganism is a causative agent of infectious dandruff. This being the case, then the use of an antiseptic on naturally occurring infectious dandruff or on artificially induced dandruff by means of pure cultures of the specific micro6r- ganism, should kill such organisms and result in the elimination of the infection. This would be 13articu- larly significant if such a result were obtained in treating infectious dandruff artificially produced with pure cultures of the causative or- ganism. This would be indirect proof of the etiological relationship of the.specific organism to infec- tious dandruff. Such a test was conducted on rabbits by Durfee and Cousins (22) using pure cultures of P. ovale to produce infectious dandruff and an antiseptic of low surface tension to treat the infection after it was es- tablished. In order to test the value of the antiseptic under such conditions an extensive series of tests was made on rabbits. The methods employed were the same as those used in their previous research on the eti- ology of infectious dandruff. Both sides of the rabbits were shaved down to bare skin and then scarified and inoculated with pure cultures of Pityrosporum ovale. After typical dandruff scaling had set in, one side of each rabbit was treated with the antiseptic and the other side left untreated as a control. The antiseptic was applied once daily on some of the rabbits and twice daily on the others. Although typical dandruff scaling covered both sides of the rabbits before treatments were started, the areas treated with the antiseptic showed marked improvement within a few days and complete elimination of scales within two weeks. The aver- age number of days after treatment

ETIOLOGY OF INFECTIOUS DANDRUFF 97 with the antiseptic when definite improvement was noted was 3.7 days, while the dandruff symptoms entirely disappeared in an average of 12 days. In virtually every case the control untreated areas, on the other hand, continued to show scaling throughout the period of the test, which lasted between three and four weeks. These results proved that the antiseptic was ca- pable of giving relief from artificially produced dandruff symptoms. Microscopic examinations were also made of the dandruff scales from the treated and untreated sides of each rabbit throughout the entire test period, the presence or absence of Pityrosporum ova/e being noted. Examination of the scales of the treated side of these rabbits showed that the infectlye organism had entirely disappeared from the skin at the time disappearance of the symptoms of the disease was noted. The scales from the con- trol side of these rabbits, however, in almost every instance showed the presence of Pityrosporum ovale throughout the entire period of the test. This series of practical tests proved that (1) the inoculation of P. ovale into the skin of rabbits caused typical infectious dandruff, and (2) the application of an anti- septic killed the infectious organism in the infected area and eliminated the evidences of infectious dandruff. It is of interest to note that cer- tain other investigators have ob- tained similar results with the use of antiseptics on naturally occurring dandruff. For example, Savill (4) found that Pityrosporum ovale was present in large numbers on dan- druff-infected scalps, but after the use of antiseptics the organism was not observed on the scalps of many of the treated patients and the dandruff had also disappeared. Also Hodges (23) reported extremely gratifying results from the use of an antiseptic in the treatment of in- fectious dandruff. CONCLUSIONS 1. A casuative agency in infec- tious dandruff is the yeast-like fungus named Pityrosporum ovale having well-defined morphological, cultural, and biochemical charac- teristics. 2. Pityrosporum ovale (a) was always found in infectious dandruff scales (b) was isolated and grown in pure culture from these scales (c) when pure cultures were rein- oculated into the skin and scalp of human subjects and the skin of rabbits the symptoms of infectious dandruff were artifically produced and (d) the same organism was then reisolated from the scalp and skin of these experimentally infected subjects. This evidences an etio- logical relationship between Pity- rosporum ovale and infectious dan- druff. 3. When an antiseptic was used in treating artificially produced dandruff symptoms on the skin of rabbits the concentration of the organism Pityrosporum ovale was quickly reduced and the symptoms of the infection were eliminated from