ORGANIC ANTISEPTICS *7 



flavour results from this application; and an injurious influence on health i.s 

 the less likely, since the peroxide is quickly decomposed. A reduction of the 

 dose below i per mil would naturally interfere with the efficiency of the reaction, 

 a circumstance which explains the unfavourable results obtained by other 

 experimenters, reported by A. SCIIROIIK (I.). A proposal, worthy of being 

 followed up, has been made by A. GOTTSTEIN (II.). A sample of water contain- 

 ing 1000 bacteria per i c.c. was found to evolve bubbles of gas at its upper edges 

 fifteen minutes after the addition of H 2 O 2 , the gas being oxygen liberated from 

 the peroxide by the activity of the microbes. Since the extent of this evolution 

 of gas fluctuates in accordance with the number of living bacteria present, this 

 behaviour might perhaps be utilised in arranging a simple method for controlling 

 the efficiency of water niters at frequent intervals. No appliances beyond a 

 stock of hydrogen peroxide and sterilised test-glasses would be required. Of 

 course, this crude method neither could nor should be used to replace the 

 examination of the efficiency of the filter by bacteriological tests, but is intended 

 for the sole purpose of enabling the engineer in charge to convince himself, every 

 quarter of an hour (or at other selected intervals), that the filtrate has fewer 

 bacteria than the unfiltered water. According to the critical researches of 

 HUGO LASER (I.), the Gottstein method is not sufficiently reliable. 



Milk of lime is, when fresh, a fairly good disinfectant, but loses its disinfect- 

 ing property as soon as the calcium hydroxide becomes converted into carbonate, 

 the latter being innocuous towards many organisms, and even favourable to 

 others (especially the acid-forming microbes). In the absence of other disinfec- 

 tants this liquid may be successfully used. According to the researches of E. 

 PFUHL (I.), it is sufficient to add two volumes thereof, and leave them to react 

 for ark hour, to ensure the death of the typhus bacilli and cholera bacteria in 

 liquid fa?cal matter. L. STEUBER (I.) has made several experiments as to the 

 influence of milk of lime on yeast-cells, and on its suitability for disinfecting 

 brickwork in the brewery. 



80. Organic Antiseptics. 



The antiseptic most appreciated next to sublimate in surgery, viz., 

 carbolic acid (Phenol, C 6 H 5 OH), which is used as a 4 per cent, solution for 

 washing wounds, is never employed for industrial purposes. Nevertheless, it 

 merits brief mention here because the discoverer of its antiseptic action, viz., 

 J. LEW AT HE (I. and II.), established the interesting fact that this constituent of 

 coal-tar, whilst capable of restricting the development of organised ferments, 

 leaves the efficiency of the enzymes unimpaired, a differential behaviour which 

 afforded support to Pasteur in his campaign against the Liebig theory of fer- 

 mentation. The toxic action of phenol on the individual species of the bacteria 

 varies, a circumstance which is utilised in the bacteriological analysis of water. 

 In order to determine if the water under examination for impurities contains 

 Bacterium coli commune, a small quantity is, in accordance with Pere's sugges- 

 tion, placed in bouillon containing one part of carbolic acid ptr mil. This will 

 retard the development of most of the water bacteria, but not that of B. coli 

 commune, which will therefore increase in the culture, and can then be more 

 readily detected by supplementary means (plate cultures). Crude carbolic acid 

 is soluble with difficulty in pure water, but readily so in sulphuric acid, com- 

 bining therewith to form sulpho-acids, an aqueous solution of which, under 

 the name of aseptol, is employed in surgery. According to the researches of 

 R. Koch, the strength of aqueous carbolic acid solution requisite to prevent 

 the germination of the spores of B. anthracis is I part in 850. In a 5 per cent, 

 solution the death of these spores is caused only after more than forty days. 



