I•LORA OF SCALP AND DANDRUFF 127 Actinomycetes--Eight resident actinomycetes were isolated. All were members of the genus Streptomyces. They were not identified to species. Actinomycetes were found in 21.4% of subjects with dandruff and in 4.5% of those without dandruff. One subject with dandruff had two strains of Streptomyces. All others with actinomycetes had one species. Entire Resident Flora--A total of 225 resident organisms were iso- lated. They ranged in number from one to eleven organisms per sub- ject. The average number of species per subject with dandruff was 5.5 and the average number per subject without dandruff was 3.0. The average number of species per individual in the four groups of resident flora is listed in Table VIII. The prevalence of the entire resident microbial flora divided into groups is considered in Table IX. Table VIII Average Number of Species of Resident Flora per Individual Group Subjects Subjects with without Dandruff a Dandruff a Yeasts • 1.4 1.1 Molds 3.1 2.3 Bacteria 2.3 1.3 Actinomycetes c . ..... Total Flora 5.5 3.0 • Only those subjects with the specific group of microorganisms were considered. b Results do not include P. ovale and P. orbiculare which were considered by direct smear (see Tables II and III). c Not enough isolates to warrant inclusion. Table IX Prevalence of the Entire Resident Microbial Flora in Persons with and without Dandruff Group Percentage Percentage Percentage of Subjects of Subjects of All with without Subjects Dandruff Dandruff Yeasts 44.2 56.4 29.2 Molds 100.0 100.0 100.0 Bacteria 42.3 57.1 25.0 Actinomycetes 13.5 21.4 4.5

128 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ]_)ISCUSSION Questionnaire Survey As previously mentioned, there are disadvantages to this type of questionnaire in which conclusions are based upon personal opinion. The fact that 70.1% of our students stated they had a dandruff problem agrees with the estimate of 70% incidence of this affliction in the United States (44). The prevalence of dandruff in our survey also agrees with other estimates that dandruff occurs in 75 to 95% of American scalps (45). Levine (46) and Templeton (47) consider it a "rarity" to find human subjects who are "normal," that is, those who are not "infected" in some way or who show no evidence of excessive oiliness, dandruff, inflamma- tion, or baldness. Templeton's evidence is based on the visual observaq tion of several hundred scalps and the finding of only 26 "normal" sub- jects. Our results show that while it is difficult to find subjects with unaffected scalps, it is not as rare as reported by these workers. The Relationship of Scurf Weights to Dandruff The separation of subjects into those with dandruff and those without dandruff was based upon the obvious relationship of scurf weights to dandruff. In this research 40 mg was the weight selected for separation for the reasons explained under "Materials and Methods." However, it should be fairly stated that individuals with a scurf weight above 40 mg do not necessarily have dandruff. This figure was true for the specific group of subjects which we studied using the two- minute HairVac technique, following the specified regimen, and during the sampling period of March to May. If any one of the above criteria is varied, the scurf weight will change. Mitsutsugu and Abe-Tsutomu (48) noted that the total scurf weight was lowest in mid-August and greatest in mid-June. Therefore, if the sampling period were in August, the separation figure might be lower than the 40 mg and if the sampling period were in June, then the figure might be higher. It was observed by VanderWyk and Roia (8) that, after continued use of antimicrobial agents, there was a leveling off of scurf weights which could not be lowered. These levels were referred to as "threshold levels," and they varied from 13 to 95 mg in different individuals. How- ever, in seven of the nine subjects studied, the "threshold level" was below 40 rag. In all instances, when the "threshold level" was reached, regardless of scurf weight, there was a marked alleviation of dandruff.