5 ANIMAL CHEMISTRY LECTURE III. 



ficially produced by a reaction of mineral on organic substances. 

 In all cases, however, either an organic substance or a body 

 derived from the organic kingdom is indispensable to this conver- 

 sion. . . . The principal sources of hydrocyanic acid are 

 certain metallic cyanides. But these compounds have an organic 

 origin ; they are the products of a reaction of organic upon inor- 

 ganic substances ; hence the production of hydrocyanic acid by 

 their decomposition furnishes no exception to the remark above 

 made. Under this point of view, the production of artificial 

 urea from hydrated cyanate of ammonia is simply a conversion 

 of cyanic acid (a derivative of an organic substance) into an- 

 other organic compound. By no processes yet known can gum, 

 starch, or sugar be produced from their elementary constituents 

 C, H, O ; and by the production of alcohol from a mixture of 

 sulphuric acid, olefiant gas, and water, Berthelot has merely 

 proved that a hydrocarbon of organic origin or one derived from 

 organic matter is capable of being converted into another organic 

 product.' Thus the view very generally entertained but a few 

 years back was substantially this that the chemist could not 

 produce organic out of mineral matter ; he might transform one 

 kind of organic matter into some allied kind of organic matter 

 starch into sugar, and olefiant gas into alcohol, for instance ; he 

 might produce certain simple organic principles by the breaking 

 up of more complex molecules oil of spiraea, for instance, from 

 salicin, alcohol from sugar, and glycerin from fat ; and he 

 might even produce highly complex principles, by a conjunction 

 of two or more simple principles oil of wintergreen by com- 

 bining salicic acid with wood spirit, and fat by combining stearic 

 acid, for instance, with glycerin ; but this was the limit of his 

 powers he might shuffle about the residues of existing organic 

 compounds in a variety of ways, but was utterly unable to 

 produce even the simplest of them by elemental synthesis. 



(6 1.) Our present knowledge, however, assures that these 

 opinions are altogether without foundation. Already hundreds 

 of organic principles have been built up from their constituent 

 elements, and as I have previously said, there is now no reason 



