EtTECT OF ANTISEPTICS AND DISINFECTANTS ON BACTERIA. 35 



of albuminate of mercury is redissolved when there is an excess of 

 albumin present. 



Geppert, and later Behring, recognised that the methods employed 

 for testing the eificacy of corrosive sublimate were um-eliable. Thej^ 

 found, for example, that corrosive sublimate could not be removed 

 from silk threads by washing ; and therefore to study the effect of 

 this antiseptic acting for a given time, it was necessary to dip the 

 threads in ammonium sulphide solution after the treatment with 

 corrosive sublimate. 



The author confirmed the results of Geppert and Behring, and 

 made a series of experiments to test the value respectively of carbolic 

 acid and corrosive sublimate in antiseptic surgery. The method 

 of dipping an infected thread into an antiseptic solution for a few 

 minutes, and then transferring it to the surface of a nutrient medium 

 to test its efficacy in a given time, was discarded as fallacious ; the 

 thread being still wet with the solution when transferred to the 

 medium, it was obvious that the action of the antiseptic continued 

 for many, days. To wash infected silk threads with alcohol after 

 exposure to the antiseptic to stop its further action, also proved to 

 be a fallacious method, for the author found in control experiments 

 that absolute alcohol will destroy Streptococcus pyogenes, erysipelatis, 

 and Staphylococcus pyogenes aureus, acting for only one minute. 

 Other methods were therefore resorted to, and cultures on the 

 sloping surface of nutrient agar were at first used. The antiseptics 

 was poured into the culture tube until the growth was covered, 

 and when it had acted for a definite time (one minute, five minutes,, 

 or fifteen minutes) a solution was added which immediately stopped 

 further action. In the case of corrosive sublimate, ammonium sul- 

 phide was employed, which is quite inert as an antiseptic. The liquid 

 contents of the test tube were carefully poured off, and an inoculation 

 was made into a fresh tube of broth or agar from the culture still 

 adhering to the surface of the nutrient medium. As the results 

 disproved the efficacy of corrosive subhmate, it was thought possible 

 that the solution had not been able in the time to penetrate the 

 film of growth. Another plan was accordingly adopted. Cultures 

 were made in broth, and when fully developed the supernatant liquid 

 was carefully poured off. Corrosive sublimate solution was added to 

 the test, tube, and agitated until any flocculent masses were dis- 

 integrated and the whole of the liquid became uniformly turbid. 

 Ammonium sulphide was added when the time had expired, and 

 tubes of fresh broth were inoculated with the mixture. In the case 

 of carbolic acid the cultures, after its action, were thoroughly washed 



