ANTIGENIC STRUCTURE 963 



several months. Purified influenza virus, on the other hand, is destroyed by 

 0-5 per cent, phenol at 4° C. within a week (Knight and Stanley 1944). Gordon 

 (1925) found that vaccinia virus was destroyed by 50 per cent, ethyl alcohol, 

 50 per cent, methyl alcohol, and 50 per cent, acetone within an hour at room tem- 

 perature ; 20 per cent, ethyl alcohol, 10 per cent, methyl alcohol, 10 per cent, 

 acetone, and 20 per cent, ether failed to destroy it in 24 hours ; even 50 per cent, 

 ether did not destroy it completely in this time. Potassium permanganate was found 

 to be extremely viricidal, destroying it even in a 1/10,000 solution within an hour 

 at room temperature. Chloroform is said to be very much more destructive than 

 ether, alcohol, or acetone (Reynals 1928). The foot-and-mouth virus is resistant 

 to concentrations of phenol, lysol, toluol, hydrogen peroxide, chlorine, iodine, 

 acetone, and chloropicrin that rapidly destroy vegetative bacteria ; but it is killed 

 by 0-1 per cent, formol at 26-27° C. in 24 hours, and by 2 per cent, antiformin or 

 0-4 per cent. HgClj within 24 hours. The effect of bile salts varies according to 

 the species of virus (Smith 1939). Influenza A and louping-ill viruses are inacti- 

 vated almost instantaneously by exposure at room temperature to a final concen- 

 tration of 1/1,000 sodium deoxycholate, whereas vaccinia and ectromelia viruses 

 are unaffected after 2 hours. Inactivation of susceptible viruses is thought to 

 be due to lysis. Certain soaps and unsaturated fatty acids, and some synthetic 

 detergents, have been found to have a strong destructive action on influenza 

 virus (Stock and Francis 1940, Knight and Stanley 1944). 



With the very doubtful exception of the lymphogranuloma virus (MacCallum 

 and Findlay 1938, Rodaniche 1942), the mouse pneumonia virus, and the 

 viruses of trachoma and inclusion blennorrhoea (Rake et al. 1942), the viruses 

 are insusceptible to sulphonamides. Penicillin likewise appears to be without 

 action. 



Metabolism. — Practically nothing is known about the metabolism of the 

 filtrable viruses, one of the great hindrances being the impossibility of cultivating 

 them in the absence of tissue cells. In purified suspensions of vaccinia virus 

 Parker and Smythe (1937) could demonstrate no oxygen consumption. On the 

 other hand Macfarlane and Salaman (1938) and Macfarlane and Dolby (1940), 

 though finding no evidence of dehydrogenase activity, were able to demonstrate 

 the presence of phosphatase and catalase ; both ribonucleic acid and adenylic 

 acid were rapidly hydrolysed. It is not yet clear, however, whether these enzymes 

 form an integral part of the elementary bodies or are derived from the host tissues 

 (see Smadel and Hoagland 1942). The ability to oxidize cysteine has been traced 

 to the presence of copper in vaccinial elementary bodies (Hoagland et al. 1941). 

 Flavin and biotin have also been found (see Rivers 1943). What part these 

 various enzymes play in the metabolism of the larger viruses under natural con- 

 ditions, it is too early to say. 



Antigenic Structure. — Although the study of the antigenic structure of viruses 

 is as yet in its infancy, enough has been learned to show that, in this respect, viruses 

 differ in no essential way from bacteria. The presence of precipitins in the blood 

 serum of animals inoculated with vaccinia virus has been reported by several 

 workers (see Sobernheim 1925). Gordon (1925) found agglutinins and complement- 

 fixing bodies in the serum of rabbits inoculated with vaccinia, active up to a dilution 

 of 1/100-1/200 ; both antibodies were specific in the sense that they reacted solely 

 with vaccinia and variola virus suspensions, and gave no reaction with varicella 

 virus, sterile pus, or brain suspensions from encephalitis lethargica. In general. 



