8 I. INTRODUCTION TO VIRUSES 



from the normal healthy skin. It is evident, therefore, that no virus- 

 like particles are present in the normal skin tissue. The writer was 

 able, however, to ascertain that, on the injection of toxic agencies such 

 as staphylococcal toxin or sapotoxin, the akin tissue would give rise to 

 particles similar to vaccinia virus which could readily be separated as 

 in the case of virus infection. Thus virus-like particles can also be 

 produced by a proper stimulus, without virus, in the cell in which no 

 particles can be detected normally. In the case of the skin tissue, 

 therefore, it may be said that protein capable of coagulating into minute 

 bodies is produced by the effect of a virus which provides to the protein 

 with the virus activity. 



