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Ultraviolet (UV) light therapy was given over a period of several weeks to 19 test persons on one side of the back. The duration of the treatment was gradually increased from 30 sec to 7 min. After conclusion of the treatment quantitative lipid determination was made on both the treated and the untreated sides of the back, using the direct extraction method and the paper absorption method. The lipids obtained in this way were analysed by thin-layer chromatography. The following were the most important results: (1) The amount of skin surface lipids was significantly increased by UV irradiation. This results goth from an increase in the epidermal lipids as well as in the lipids of the sebaceous blands. (2) The percentage of free cholesterol in the skin surface lipids was significantly increased by UV irradiation. This increase is probably connected with a thickening of the stratum corneum. (3) The percentage of free fatty acids in the skin surface lipids is significantly increased by UV therapy. This shows that the living conditions of the saprophyte skin flora, which set free lipases, are improved as a result of this treatment or that this treatment leads to an increase of the activity of the bacterial lipases in the excretory ducts of the sebaceous glands.

Measurements of the water content of the stratum corneum were made on the flexor side of the forearm in healthy male volunteers using direct current resistance and alternating current (1.5 and 15 kHz) electric impedance measurements, capacity measurements and measurements of transepidermal water loss. In addition, infrared-spectroscopic investigations were made using a Frustrated Multiple Internal Reflection device on unstripped skin, then on the same skin area after five and ten strippings with adhesive tape. The tests showed (except for the measurements of transepidermal water loss) all of the aforementioned test methods led to relevant measurement values. While the direct current electrical resistance measurement yielded data on the water content of the most superficial layer of the stratum corneum, it was found that the capacitor measurements gave results from the deep layers of the stratum corneum. With the alternating current impedance measurement method, both superficial and deep layers of the stratum corneum were taken into account. Comparative measurements of direct current resistance and infrared absorption after occlusion treatment revealed that under certain circumstances using both methods can lead to contradictory results.

Biochemical and physiological examinations were carried out on the healthy surface of the skin of 24 test persons who had had contracted common warts during the 2 years prior to examination and on a control group of 46 healthy persons of the same age and sex. The following significant results were obtained: (1) There was a significant reduction in the percentage amount of squalene in the lipids of the skin surface in the patients with common warts as compared with the healthy control persons. (2) The alkali neutralization time in the patients with common warts was significantly shortened as compared with the healthy control group. (3) The degree of moistening of the skin with water was significantly less in the patients with common warts than in the control persons. These results indicate important predisposing factors for common warts.