772 A MANUAL OF BACTERIOLOGY 



It will be seen that Flavine is the only one of these 

 which is more active in serum, and it does not inhibit 

 phagocytosis until a concentration of 1 : 500 is attained. 

 On these grounds its use has been strongly urged for 

 surgical practice. Browning's results with Flavine have, 

 however, been criticised by Fleming and by Hewlett ; 

 moreover, its action is exerted extremely slowly. 



Chloroform is a powerful antiseptic, but at least 1 per 

 cent, must be present to act as a germicide ; it is costly, 

 and not much used as a practical disinfectant, but in 

 bacteriological and physiological chemistry is a useful 

 antiseptic for preserving solutions which putrefy easily. 



lodoform is valuable for dusting wounds, though its 

 penetrating odour is objectionable, and has led to the 

 introduction of many substitutes. Its value as an anti- 

 septic has been greatly discussed ; micro-organisms will 

 develop in nutrient media containing a considerable 

 proportion, but probably when in contact with living 

 cells a decomposition is effected, free iodine being 

 liberated, hence its value. A paste, known as B.I.P., 

 composed of iodoform, bismuth subnitrate and liquid 

 paraffin, has been used in the treatment of wounds. 



The essential oils, peppermint, mustard, cloves, thymol, 

 and menthol, are powerfully -antiseptic. 



Disinfectant powders at best exert but a superficial 

 action. They act chiefly as deodorants, but may be useful 

 in preventing the breeding of flies in garbage, etc. 



It is useless to add a small quantity of disinfectant to a large 

 volume of fluid or solid ; the disinfectant must be added in 

 sufficient amount so that the mixture contains the minimum 

 percentage which has been found by experiment to be efficient. 

 For this reason the attempt to disinfect sewers, sewage, streets, 

 etc., by relatively small quantities of disinfectants is useless, 

 and the money so wasted would be far better employed in pro- 

 viding more water for flushing purposes, 



