NOTICES OF BOOKS. 55 



Group I. — Gums. 



A. True Gums, a. Arabic kind [Acacia arahiea). (3. Cherry kind 

 (Prunus Cerasus). 



B. P.mido-GumSy a. Tragacanth kind {Sterculia ursns). /8. Dackor 

 Moringa {Moving a pterygosperma'). 



C. Astringent Gums. Buteafrondosa. 



Group II. — Gum-Eesins. 



A. Emulsive (Gamboge). B. Fcstid (Asafoetida) C. Fragrant, 

 a. Bdellium kind (Googul). ft. Benzoin kind (Benzoin). 



Group III. — Kesins. 



A, Hard or Copalline. a. Pale resins ( Vateria indica), jB. Dark 

 resins (Black Dammar). B. Soft or Elemi {Cana/rium commune). 



Group IV. — Oleo-Resins. 



A. Balsams (Wood oil). B. Varnishes (Burmese lacquer). 0. 

 lurpentine and Tar. 



In explanation of this arrangement Dr. Cooke says that, ''Hitherto 

 no classification has been attempted of these products, and in all lists 

 prepared a merely mechanical or alphabetical arrangement has been 

 adopted. The method which commended itself as most serviceable for 

 commercial purposes was one which bore some relation to the function 

 of the substance under report, a method already adopted in respect of 

 East Indian fibres, and which practically has been found to answer its 

 purpose." 



The four groups into which the products have been divided. Dr. 

 Cooke thinks, will require very Httle explanation beyond that which 

 the table affords ; nevertheless, he proceeds to explain that it has been 

 found necessary to place some of the true gums alphabetically under 

 the first group, because then separation into the Arabic and Cherry 

 kinds " could not be wholly completed in default of specimens for ex- 

 amination." Notwithstanding that he further explains that the Pseudo- 

 Gums are those which like Tragacanth swell in water but do not dis- 

 solve ; that the Astringent group includes the kinds which might 

 perhaps be better classed with Cutch and Gambler ; and that the 

 Emulsive series are those which mix with water like Gamboge, we 

 cannot but think that the arrangement is not that which will be '* most 

 serviceable for commercial purposes." "We are satisfied that an alpha- 

 betical arrangement is the one most suited for business men, and this, 

 carried out with a good index of genera and species, would make it 

 equally useful to the man of science. The Report, however, has not 

 a shadow of an index, so that without some previous knowledge of the 

 nature of the gum or resin required, it is not an easy matter to 

 find it. In making these remarks we do not disparage the work before 

 us, for there can be but one opinion as to the value of the facts here 

 brought together. 



J. R. J. 



