150 DISINFECTION 



(8) The higher the temperature at which a disinfectant is allowed to act, the 

 more rapid is the process of sterilization. 



(9) Some germicides dissolved in alcohol or in vegetable oils are deprived of 

 the greater part of their power, but an alcoholic solution of iodine is a potent 

 skin disinfectant. 



(10) Doubling the concentration of HgClg halves the time taken for sterilization ; 

 doubling the concentration of phenol diminishes it about 64 times. 



(11) For use in a protein medium, the acid disinfectants, such as hypochlorous 

 acid, bleaching powder, and the disinfectants that can be employed combined 

 with acids, are most effective. The alkalies are also reliable. 



(12) In the presence of organic matter, whether in solution or in suspension, 

 the activity of certain disinfectants is markedly lowered, especially with the emul- 

 sified disinfectants, with oxidizing agents, and with the salts of the heavy metals. 

 Phenol is much less affected, and likewise certain dyes, such as flavine. 



(13) Salts of the heavy metals — mercury, silver, and copper — are mainly of 

 value for their bacteriostatic effect ; their ability to kill bacteria has been grossly 

 overestimated in the past, and is in reaUty comparatively low. 



(14) For the disinfection of varnished or greasy surfaces, an emulsified dis- 

 infectant or a bactericidal wetting agent is to be recommended ; aqueous solutions 

 are of little value. 



(15) For the disinfection of metal instruments, all substances that act on the 

 metal, causing rust or other change, must be avoided. 



(16) For references to disinfection of the hands and skin, the following papers 

 may be consulted : Ahlfeld and Vahle (1896), Colebrook (1930, 1941), Colebrook 

 and Maxted (1933), Neufeld and Schiemann (1943). 



(17) For instructions in the use of liquid disinfectants in hospitals, see Report 

 (1944). 



Solid Disinfectants. — These are generally made up in the form of powders, with 

 a basis of lime, silicious matter, or vegetable fibre. Phenol is the commonest dis- 

 infectant incorporated. To destroy bacteria they must pass into solution ; , in 

 the dry state they act merely as deodorants. 



REFERENCES 



Ahlfeld, F. and Vahle, F. (1896) Dtsch. med. Wschr., 22, 81. 



Albert, A. (1942) Lant.et, ii, 633. 



Allen, P. W. (1923) J. Bad., 8, 555. 



Andrewes, F. W. and Orton, K. J. P. (1904) Zbl. BaJcL, 35, 645, 811. 



Apostoli, G. and Laquerriere, A. (1890) C. R. Acad. Sci., 105, 918. 



D'Arcy, R. F. and Hardy, W. B. (1894) J. Physiol, 17, 390. 



Baker, Z., Harrlson, R. W. and Miller, B. F. (1941a) J. exp. Med., 73, 249 ; (19416) Ibid., 



74, 611, 621. 

 Bancroft, W. D. and Richter, G. H. (1931) J. phys. Chem., 35, 511. 

 Barnard, J. E. and Morgan, H. de R. (1903) Proc. roy. Soc, 72, 126. 

 Barnes, J. M. (1942) Lancet, i, 531. 

 Barr, C. E. (1923) J. med. Pes., 44, 79. 



Baxter. (1875) Rep. loc. Govt. Bd. publ. Hlth., New Ser., No. 5, appendix p. 216. 

 Bayliss, M. (1936) J. Bact., 31, 489. 



Bayliss, W. M. (1924) " Principles of General Physiology," 4th ed. London. 

 Beattie, J. M. and Lewis, F. C. (1920) Spec. Rep. med. Res. Coun. Lond., Ser., No. 49. 

 Beckman, J. W. (1896) Zbl. Bakt., 20, 577. 



Beckwith, T. D. and Olson, A. R. (1932) Proc. Soc. exp. Biol, N.Y., 29, 362. 

 Beckwith, T. D. and Weaver, C. E. (1936) J. Bad, 32, 361. 

 Behrino. (1890) Z. Hyg., InfektKr., 9, 395. 



