68 Appendix. 



Again, boil the almond pulp with dilute sulphuric acid, and the 

 bitter almond oil and prussic acid and glucose appear with an- 

 other product, formic acid. Vinegar may be rapidly formed 

 from alcohol, in the air, (i) when at ordinary temperature there 

 is the contact of a certain species of living cells; (2) when, 

 without cells, there is platinum black present ; (3) when, without 

 cells or porous body, the oxygen is nascent ; the change being 

 in each instance through aldehyde by the same equation. Now, 

 if the styrax benzoin contained naphthalin, it would not cer- 

 tainly follow that the benzoic acid of the plant was formed from 

 this naphthalin, through phthalic acid, because such is the case 

 in the factory. 



In the second place, as foundation for a study of the chem- 

 ical history of aromatic bodies in plants, we have but a very 

 limited knowledge of the constituents of plants in general. The 

 analytical work in organic chemistry is behind the synthetical 

 work. The proximate analysis of plants needs to be made as 

 thorough as possible : no constituent can be assumed to be unim- 

 portant. As an illustration, it was stated above that in a certain 

 summary of plant constituents, of 45 orders reported to contain 

 volatile oils, 29 were not reported to contain resins. Consider- 

 ing the known methods of analysis and the ordinary purposes of 

 analysis, the question arises, how many of the plants analyzed in 

 these 29 orders do nevertheless contain resins ? And, taking a 

 given plant known to contain both resin and volatile oil, what 

 results might not come from a series of careful quantitative 

 analyses of the plant in different stages of its growth and of dif- 

 ferent parts of the plant? Before the natural formation of 

 carbon compounds can be traced, and before generalizations as 

 to nature's chemical methods can be attained, an enormous 

 amount of work has to be done. 



In this discussion, it is of course taken for granted that the 

 molecules of matter are formed afid conserved by chemism ; as truly 

 in the plant as in the rock. Chemism may be, as has been held, 

 due to an attractive force ; or it may be due to harmonies and co- 

 ordinations of atomic motion, rotatory or oscillatory ; molecules 



