SOME EXPERIMENTS WITH DISINFECTANTS 19 



Other groups, such as carbolic acid, &c. He found that suspensions of 

 the Staphylococcus pyogenes in sterile water were destroyed by a 

 1-500 solution of corrosive sublimate in 12J minutes, and by a 1-1,000 

 solution in 50 minutes, while beef-tea cultures of the organism required 

 for their destruction with similar dilutions of the disinfectant, 45 minutes 

 and 4 hours respectively. These results illustrate remarkably well a 

 point upon which Andrewes has laid great stress — the fact, namely, that 

 the presence of organic matter exercises a distinctly retarding influence 

 on the germicidal action of corrosive sublimate. 



Cyllin is the new name for creolin, as manufactured by Jeyes' 

 Disinfectant Co. Its composition, however, is not quite identical with 

 the fluid sold until recently as "creolin," but has been modified with a view 

 to obtain the highest germicidal value with the lowest possible toxicity 

 to higher animals. It is stated to contain no carbolic acid or its 

 homologues, and to rely solely for its high efficiency on certain members 

 of another chemical series which have been recently isolated. It forms a 

 slightly pinkish emulsion when mixed with water. 



Klein, in a series of experiments, completed after my own investiga- 

 tions had been largely carried out, compared the action of cyllin, 

 formaline, and carbolic acid on B. pestis, and found that a solution of 

 1-30 formaline did not kill B. pestis. On the other hand, a solution of 

 1-80 carbolic acid killed B. pestis after 10 minutes' exposure, and a solution 

 of 1-2400 cyllin killed B. pestis after 10 minutes'. Klein concludes 

 from these experiments, that the germicidal power of a 1-2,400 solution 

 of cyllin is equal to that of a 1-80 solution of phenol, and greater than a 

 1-30 solution of formaline. Therefore, the disinfecting power of cyllin is 

 about 30 times as great as that of phenol, and more than 80 times that 

 of formaline. These results are certainly very striking. It ought, how- 

 ever, to be mentioned that the experiments were apparently undertaken 

 at the instance of the makers of cyllin. How far my own experiments 

 agree with these will be seen later. They were undertaken without any 

 communication with the makers, and the cyllin was purchased in the 

 ordinary way. 



Izal. — A non-poisonous disinfectant obtained as an oil from the by- 

 products in the making of coke. Izal, as it appears on the market, is a 

 40% emulsion of this oil. It forms a light fawn-coloured emulsion when 

 mixed with water. 



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