PROTEINS, PEPTONES, AMINO-ACIDS 223 



quantity of a white powder — about half a teaspoonful. Each 

 powder consists of the same elements, oxygen, hydrogen, nitrogen, 

 and carbon. One is practically harmless ; the other contains 

 within it the power of death to a thousand men. The one is 

 quinine, the other aconitia — the alkaloid which makes so deadly 

 the plant whose flower our ancestors called monkshood, in the 

 far-off days when the original was often before their eyes. It is 

 an almost startling fact that in this minute quantity of powder, 

 hardly visible to those at a distance, there is such a potentiality of 

 death. Picture to yourselves a thousand men. That which is 

 in this tube would end the life of every one of them. Here is a 

 latent power beside which the lightning flash is feeble, and to 

 which the earthquake might give place, as far as the comparison 

 depends on lethal certainty. 



" But the resemblance in the aspect of these two substances 

 is not all. As I said, each consists of the same elements — each 

 is made up of carbon, nitrogen, oxygen, and hydrogen. Each 

 consists of the elements which compose air and water, with 

 carbon added. Why is one almost harmless and the other a 

 most deadly poison ? I might ask the question regarding many 

 other substances composed of the same elements, but between 

 these two the resemblance is strikingly close. The answer to 

 my question may be given, ' It depends upon the chemical 

 constitution.' True, but this takes us a very little way. When 

 we discern that the difference depends upon the way in which 

 the elements are arranged in molecules, and the molecules are 

 grouped together, we are not much nearer an explanation. We 

 see a little more, however, when we realize that chemical con- 

 stitution means that energy is held ' latent ' (as it is said), ready 

 to be released when the elements form simpler, closer com- 

 pounds. All vital function of the body depends on a like simpler, 

 closer union of the elements which make up complex organic com- 

 pounds. As far as we can see, all the energy which is released in 

 the animal body, is released in consequence of chemical action 

 under the mysterious influence of life. Where such closer union 

 of the elements and such release of latent energy are going on, 

 the process may be changed entirely by the contact of molecules 

 of allied constitution, with latent energy on the point of release, 

 so held as to blend with that which is being set free in the living 

 tissue. Blending with this, it may augment or oppose. Re- 



