16 INTKODUCTION 



m states that the antiseptic principle is destroyed by 

 boiling and he considers himself warranted in affirming that 

 it is a volatile substance. To my mind there is no doubt that 

 this antiseptic action ought in reality to be assigned to 

 the bacteriophage. 



The second publication is that of Twort 2 entitled "An Investi- 

 gation on the Nature of the Ultramicroscopic Viruses." In the 

 course of his experiments upon the filtrable virus of vaccinia this 

 author obtained on certain of his agar slants inoculated with the 

 glycerinated vaccinal pulp, a culture of a micrococcus of which 

 certain colonies presented a vitreous and transparent aspect. 

 The micrococcus had been replaced by fine granules. At other 

 times he obtained a film of growth showing spots composed of 

 the same vitreous material. These colonies slowly spread over 

 the entire culture, the micrococcus everywhere being transformed 

 into granules. When a pure culture of the micrococcus was 

 touched with a platinum wire which had previously been in 

 contact with the vitreous material, a spot of the same nature 

 developed and extended gradually over the whole surface. The 

 action was feeble on cultures previously killed. The vitreous 

 substance, when diluted, passed through a porcelain filter, for a 

 drop of the filtrate transformed a normal healthy culture into 

 one of the vitreous appearance. The transformation process 

 began in isolated points and rapidly extended over the surface. 

 However, if some portion of the normal culture never came in 

 contact with the filtrate, the healthy growth regained the advantage 

 and extended over the vitreous stratum but without effecting 

 its destruction. The material of transparent and vitreous nature 

 maintained its activity for at least six months. It resisted a 

 temperature of 52C. but was destroyed at 60C. 



Twort obtained similar results with an organism of the colon 

 group, isolated from the intestinal mucosa of a dog affected with 

 Hundeseuche, and with a large bacillus not belonging to the colon 

 group isolated from the intestinal contents of an infant suffering 

 from diarrhea. In both cases the material transformed the nor- 

 mal culture into matter of a vitreous transparent aspect. 



2 An Investigation on the Nature of the Ultramicroscopic Viruses. Lan- 

 cet, 1915, ii, 1241 (December 4). 



