PINE-OIL AND PINE-DISTILLATE PRODUCT EMULSIONS. 13 



typical. The} 7 could be differentiated one from the other only by 

 animal inoculation and by the difference in resistance shown by one 

 of them to pine oil. 



In testing the pine-oil emulsions against these strains the Kideal- 

 Walker technique was used, and, in order to guard against possible 

 error through contamination, the pathogenic strains were, in at least 

 one test, passed through a rabbit after recovery from the pine oil. 



No. 200, the old stock strain, was found to be the most variable in 

 its power of resistance. It was tested against all six samples of the 

 Hygienic Laboratory pine-oil disinfectant, and gave R. W. coeffi- 

 cients ranging from none to 1. In no case, however, was it killed in 

 15 minutes by a dilution of y^. The variability of this strain made 

 it obviously unsuited for experimentation, for which reason the other 

 three strains were obtained. 



Nos. 202, 203, and 204 acted alike, and were found to resist 5 and 

 10 per cent emulsions for 15 minutes. Since 10 per cent is too strong 

 to make a satisfactory emulsion, it was evident that the product is, 

 for all practical purposes, useless against these strains in an} 7 

 strength. 



In order to test the efficiency of pine oil against the spore-bearing 

 group of bacteria, a number of experiments were made in which B. 

 anthracis was employed as the test organism. Old neutral-agar cul- 

 tures were used. To these sterile distilled water was added, after 

 which small pieces of sterile filter paper were saturated in the result- 

 ing mixture. These pieces of paper were transferred to test tubes 

 containing 5 and 10 per- cent dilutions of the pine-oil emulsion. 

 After various intervals of time the} 7 were again transferred to tubes 

 of broth, in order to free them from the pine oil, and finally trans- 

 ferred to neutral agar. The tubes were kept at a room temperature 

 of from 20° to 25° C. Two samples were tested in 10 per cent emul- 

 sion and one in 5 per cent emulsion. Under these conditions pine oil 

 failed to kill the spores of B. anthracis in 3 days. 



EMULSIONS OF DESTRUCTIVE-DISTILLED PINE OIL AND OTHER PRODUCTS OF 



DISTILLATION. 



In addition to the sample of Hygienic Laboratory pine-oil dis- 

 infectant prepared by the method described by Stevenson, there are 

 on the market a number of preparations made from inferior oils. 

 These (page 9) are known as destructive-distilled pine oil, wood 

 naphtha, crude light oil, entire crude oil, and tar oil. Experiments 

 on these preparations were carried out in the same way as those on 

 the Hygienic Laboratory pine-oil disinfectant. 



Five samples of the destructive-distilled pine-oil emulsions gave 

 coefficients ranging from 1.71 to 3.42 when freshly prepared. At the 

 end of a month the range was from 1.68 to 3.40, and at the end of 



