130 Dr. R. D. Thomson's Examinatum of the Caufdie Pine Resin. 



Carbon, . . . 

 Hjdrogen, . . 

 Oxjgen, . , . 



The comparative formula will then be — 

 C40 H31 Ofl 

 C« H35 



33-25 lOO-OO 



2 15 = 2CO2+HO 



The preceding experiments assist in carrying out certain generaKsa- 

 tions which had been deduced from a more limited series of data, and 

 serve to confirm the idea of the analogy of the resins, and of their 

 derivation from an oil of the turpentine type. 



The resins, perhaps, are more interesting to the chemist than at 

 first appears, from their analogy to other bodies of vegetable and 

 animal origin. Whether their basic oils are derived from the deoxida- 

 tion of other bodies in plants supplied with a larger amount of oxygen, 

 or are formed directly from their gaseous constituents, is subject for 

 inquiry. If it be true that plants evolve no heat, (although it is not 

 easy to comprehend how gases can be condensed without such a dis- 

 engagement,) then it would appear that no combination of carbon and 

 oxygen — ^no proper combustion, such as occurs in the animal system, 

 takes place in plants ; and hence it would follow that the essential oils 

 are formed directly from their elementary constituents. But the state- 

 ment (Brongniart,) which has been made, that plants evolve heat in 

 fertilization, that oxygen is absorbed, and carbonic acid given out, 

 would appear to favour the idea that combustion can occur in plants 

 as well as in animals. The admission of the operation of this process 

 in plants would throw much light on the following table, representing 

 a descending series, with the exception of the first, into which some 

 bodies of animal origin are introduced for the same of comparison : — 



Protein, C48 Hge O,* Ne 



Gum, .• C48 H44 0,4 



Starch, C48 H40 O40 



Base of Cane Sugar, . . C48 H36 O36 



Fat, ........ C44 H40 O4 



Bees- Wax, C40 H40 Oa 



Dammaran, C40 H3, Oe 



Cholesterin, C38 H32 



Base of the Resins, . . . C40 H32 



In reference to the preceding table, the analogies of starch and gum 

 are sufficiently apparent in the analysis of flour, while the conversion 

 of starch into sugar, by artificial methods, and in vegetation, is too 

 well known to require more than a notice. The production of wax 



