EXPERIMENTS WITH RADIUM 97 



at low temperatures and coagulate at higher ones ; 

 cyanic acid earlier, living proteid later. Their 

 similarity," says Pfltiger, "is so great that I might 

 term cyanic acid a half-living molecule." 



Pfliiger's analyses, to say the least of them, have 

 not met with widespread recognition, further ex- 

 perimental confirmation being doubtless necessary 

 before they could be ranked as theory. 



The dynamical nature of the cyanogen molecule, 

 however, together with the large store of potential 

 energy which it contains, constitutes the resemblance, 

 from a physical point of view, between it and radium 

 compounds. Still it must be borne in mind that 

 the internal energy thus manifested by the molecular 

 disintegration is of an entirely diflFerent order of 

 magnitude. Nevertheless there is a sufficient resem- 

 blance between the two from a physical point of 

 view to utilise either of them for the purpose of the 

 experiments we have in view. The molecule in either 

 case might act as a nucleus that by catalysis, or some 

 other means, should set up dynamically unstable 

 groups, which, though not living in the sense that 

 they possessed the n qualities of living proteid, might, 

 as we have said, by possessing n-1 oi those qualities 

 be regarded as a mode of life in the sense in 

 which many philosophers have used the word. 

 If cyanogen is a half-living thing, as Pfliiger 

 supposed for the reasons given, it is only natural 

 to try if it would form growths in culture media, 

 and the use of bouillon in my experiments was 

 merely the logical outcome of this conception. 



H 



