Immunity and Cutaneous Sensitization 21 



injections oi trichophytin. Wise and Sulzberger also noted this phenomenon. 

 Vrnold considered trichophytin less specific than tuberculin l>nt more 



specific than some bacterial products. Stein Found that patients with lavns 

 Tailed to react to trichophytin. Low obtained only two positive reactions 

 in 26 cases of proved ringworm infection and was disappointed in the 

 results, lie used vaccines made from strains ol Microspornm, Trichophyton 

 and Achorion. His positive results were obtained in a case of Microspornm 

 infection of the scalp and in a case of favus. Negative reactions were 

 obtained in cases of kerion and of tinea barbae. 



It was noted by Walthard and by Jadassohn and Peck that patients 

 with allergic secondary eruptions ( dermatophy rids ) regularly reacted to 

 trichophytin. Sulzberger and Lewis demonstrated that in some persons 

 an eczematous reaction was obtained to a patch test with trichophytin. 

 Rosen, Peck and Sobel, who studied the reaction to trichophytin in 102 

 patients, concluded that the test was specific. They compared the relative 

 merits of the intracutaneous, scratch and patch tests and found the intra- 

 cutaneous test to be the most reliable. No cultural studies were undertaken. 



Van Dyck, Kingsbury, Throne and Myers reported the cases of 100 

 patients who presented eczematous eruptions and others which suggested 

 fungous infections. In each instance the reaction to a commercial extract 

 of trichophytin (Metz) was positive. They used a 1:10 dilution, whereas 

 we later found that a 1:100 dilution of the same extract was capable of 

 producing reactions in susceptible subjects. Van Dyck and his associates 

 inferred that the reaction to trichophytin may displace other methods in 

 the diagnosis of fungous infections. It was later reported that 117 of 317 

 subjects had positive reactions to trichophytin similar to those previously 

 reported. Although not specifically stated, it was implied that the remain- 

 ing 200 subjects also exhibited positive reactions. The presence of a positive 

 reaction was held as the diagnostic equivalent of demonstration of the 

 micro-organism. The high concentration of trichophytin (1:10) used as 

 testing material and the absence of cultural studies, as well as the lack 

 of a suitable number of patients as controls, weaken the value of these 

 reports. 



Williams and Carpenter evaluated trichophytin in diagnosis and re- 

 ported that the reaction was positive in 51 cases of clinical fungous disease 

 in 36 of which there was microscopic verification. There was a negative 

 reaction to the test in 19 cases of clinical fungous disease, in five of which 

 the microscopic test gave positive results. In 36 control subjects, clinically 

 free of fungous disease, there was only one positive reaction to trichophytin, 

 and this could not be accounted for by the history or the physical findings. 

 Williams and Carpenter stated that false positive reactions to trichophytin 



