338 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO. 14 



amino (NHo) group from the ring as in stovaine and alypine. 



However, the power to anaesthetize the sensory nerve endings is 

 not limited to basic substances like those above described. Many 

 substances quite unrelated to them possess this power to a greater or 

 less degree, such as antipyrine, certain inorganic salts, quinoline 

 derivatives, phenolic and aromatic side-chain alcohols."*^ Some of 

 the latter, like benzyl alcohol, phenethylol, benzoyl carbinol and 

 saligenin, promise to compete with substances of the procaine type. 



That so many substances of such varying molecular configuration 

 exhibit similar physiological action arouses the suspicion that, as in 

 the case of the indifferent narcotics, some as yet unrecognized common 

 physical property is concerned in their action. Significant in this 

 connection is the fact that Schleich modified the method of terminal 

 anaesthesia by showing that if hypotonic solutions, that is, solutions 

 of a lesser osmotic concentration than the blood, be injected under 

 pressure until the tissues become rigid, the concentration of the 

 anaesthetic necessary to prove effective is reduced. Now either 

 hypotonic or hypertonic inorganic salt solutions tend to produce local 

 anaesthesia by themselves, perhaps through merely causing swelling or 

 shrinking of the cells, that is partial plasmolysis.^- It is also signif- 

 icant as bearing on the possibility of some common physical property 

 of the local anaesthetics that Gros^^ presents evidence that bases 

 like cocaine and procaine are made more active if set free by sodium 

 bicarbonate from their salts, presumably because they, like other 

 alkaloids, enter cells most readily as the free base.^^ 



The type of reasoning and experimentation which made a new era 

 in surgery possible through the development of such substances as pro- 

 caine is not limited to the production of new and valuable drugs. 

 It has been applied with success to the production of new perfumes, of 

 new antiseptics^^ and new flavoring materials. 



As an example of the application of this manner of reasoning in 

 the production of flavoring substances may be cited the work of E. K. 

 Nelson in the Bureau of Chemistry upon capsaicin, the pungent 

 principle of red pepper. Nelson first determined that capsaicin is a 



^1 H. G. Barbour. Local anaesthetics. Science N. S. 51: 497-504. May 21, 1920. 

 *2 Barbour, op. cit. 



^3 O. Gros. Ueber die Narkotika and Lokalanaesthetika. Arch. exp. Path. u. Phar- 

 makol. 63: 80. 1910. 

 " Cf. supra, p. 333. 

 *^ E. p., Dakin's Di-chloramin T. 



