404 COLLOIDS IN BIOLOGY AND MEDICINE 



animals may take the dose theoretically necessary to disinfect 

 the body, for instance, tetrabrom-o-cresol and hexabromdioxydi- 

 phenylcarbinol which, according to H. BECHHOLD and EHRLICH, 

 stop the development of diphtheria bacilli in bouillon at a dilution 

 of 1 : 200,000. In the organism they have no effect at all, in spite of 

 the fact that there may be introduced into the body without harm, 

 doses which are one hundred times that necessary to inhibit the 

 development of the bacteria in vitro or to kill them within twenty- 

 four hours. Tetrachlor-o-diphenol behaves similarly; it inhibits 

 development of diphtheria bacilli in dilutions of 1 : 400,000 to 

 1 : 640,000. Individual colonies still grew in a serum culture in the 

 presence of the chemical at a dilution of 1 : 10,000. We might 

 question whether the result was due to favorable vital conditions in 

 serum removed from a living organism or to other causes. Experi- 

 ment proved the latter view correct. By ultrafiltration the free 

 tetrachlor-o-diphenol was separated from the fraction bound to 

 serum colloids and it was found that 87.5 per cent of the disinfectant 

 had been fixed by the serum colloids. 



The relatively simple conditions in the disinfection of skin and hands 

 are especially instructive. The hands adsorb solid particles from 

 the air and particles of dirt and bacteria from dirty water (H. BECK- 

 HOLD). Upon washing with soap these particles are surrounded by 

 fatty acids or fatty acid alkali hydrolytically split off and cease to 

 cling to the hands. A priori we might conclude that there would be 

 a diminution in germs or disinfection associated with the cleaning of 

 the hands; indeed, it was shown by earlier investigators and recently 

 by H. REICHENBACH that soaps possess considerable germ-killing action. 

 I was able to prove that there exists absolute parallelism between 

 the detergent and the disinfecting action of soaps. It is impos- 

 sible to disinfect the hands with soap in any practicable time 

 (10 minutes), though this can be readily accomplished with alcohol 

 and alcoholic solutions. According to H. BECHHOLD, the reason is 

 that alcohol with its low dynamic surface tension readily enters the 

 capillary interspaces of the bare hand where the bacteria are lodged, 

 bub aqueous solutions, on the contrary, enter them very slowly. 

 This can be readily discovered by the difference in the distance they 

 ascend in strips of filter paper. 



[As the result of trench warfare the study of antiseptics in the 

 treatment of wounds has received intensive study. Antiseptic sur- 

 gery has been revived. CAKREL and DEHELLY have elaborated a 

 valuable system for the treatment of wounds by irrigation with anti- 

 septics of the chlorin group. The whole subject of wound irrigation 

 has been restudied and new antiseptics discovered. 



