Notes on scientific research. 



135 



in which the ketone group is missing is just as ineffective as thujone (VI) which only 

 differs from camphor owing to an alteration in the bridge formation, whereas both 

 these compounds by altering the experimental method (action of their vapour on the 

 frog's heart) showed themselves to be efficacious to former experimentalists 1 ). These 

 investigations also demonstrated in this modified experimental method the uniform 

 efficacy of d- and Z-camphor and the total ineffectiveness of t-camphor. Comparative 

 experiments on the action on the heart, when using various solvents for camphor 

 lead to the conclusion that every other solvent rather than oil makes the effect of 

 camphor more plainly visible. 



In reference to these theoretical reflections we should like to make the following 

 remarks: — Firstly, in ethylcamphor no methyl group is substituted by an ethyl group, 

 but rather a hydrogen atom of the methylene group next to the carbonyl one is sub- 

 stituted by ethyl. Camphor in which the methyl linked to the nucleus is substituted 

 by ethyl would be an i-ethyl-7,7-dimethylbic^cZo(i,£,,2)-heptanone, a compound which 

 is still unknown. Besides, camphenilone does not contain one methyl group mwe 





CH 







CH 







CH 





H 2 C^^ CH 2 



H 2 C 



^"p^co 



H 2 C 



<^\ ^CH-C a H 5 





C(CH 3 ) 2 







C(CH 3 ) 2 







C(CH 3 ) 2 



H 2 C^ ^-CO 



H 2 C 



\^L-^ 



CH 2 



H 2 C 



^J^Jco 



C-CH 3 





CCH 3 





C-CH 8 



(I) Camphor. 



(II) Epicamphor. 



(III) Ethylcamphor. 



CH 





CH 





CHCH 8 



H 2 C^ ^C(CH 8 ) 2 



H 2 C 



""'T^ 



C:CH 2 



HC 



r^^^co 





CH 2 







CH 2 







\ 





H 2 C^ 



CO 



H 2 C 



^J^^C(CH 3 ) 2 



H 2 C 



P^^-CH 2 



CH 





CH 





CH(CH 3 ) 2 



(IV 



1 Camphenik 



me. 







!) Camphene 







VI) Thujone 





than campher, but rather one less. Finally, thujone is not distinguished from camphor 

 by a modification of the bridge formation, on the contrary it is a compound having 

 an utterly different constitution. k 



In like manner experiments on isolated frog's hearts with the 3 camphor varieties 

 left no doubt as to the similarity of their effects from a pharmacological point of 

 view. Nor was Joachimoglu with the aid of experiments able to detect any difference 

 in their effects on bacteria. 



Joachimoglu has made experiments concerning the heart action of camphor on 

 isolated frog's hearts according to Straub's method, employing for this purpose solely 

 watery camphor solutions. With this object in view he determined the solubility of 

 camphor in water and found that one part of ^-camphor dissolves in 666 parts of 

 water, whereas one part of I- or i-camphor requires 800 parts of water in order to dis- 

 solve. For the purpose of testing the antiseptical effects of camphor the Bacterium 

 coli and the Vibrio Metschnikoff were chosen. The camphor was dissolved in sterilised 

 nutrient broth and this camphor-broth was diluted accordingly by means of normal 

 broth. After this procedure the tubes were inoculated with a broth-culture prepared 



*) Comp. W. Heubner, Therap. Monatsh. 27 (1913), 593; Report October 1913, 127. 



