436 



R. T. BAKER. 



Mr. H. G. Smith has recorded 1 calcium oxalate from the 

 bark of various Eucalypts, (10 species), obtained by break- 

 ing the bark down, boiling and then recovering the crystals. 



A very large number of instances of the occurrence of 

 calcium oxalate crystals in the vegetable kingdom are 

 given by Solereder in his "Systematic Anatomy of Dico- 

 tyledons," but the majority of these instances are in the 

 leaves, bark and root. 



In the case of the leaves he almost invariably states that 

 this substance in its various crystalline forms is excreted, 

 meaning of course in the process of metabolism. But in 

 my opinion the word "deposited" would more correctly 

 describe the action, in any case at least in the secondary 

 wood if not the leaves. Again, this fixation of lime by the 

 oxalic acid seems to prove in the opinion of the author that 

 the latter is not deleterious to the plant any more than 

 manganese, but is specially formed by the tree for this 

 particular function, in order to free the sulphur from the 

 calcium sulphate for the formation of sulphuric acid so 

 essential in the construction of albuminous substances. 



Various authors record that oxalate of lime is found in 

 several forms, viz.: — as ordinary solitary crystals, clustered 

 crystals, styloid-like crystals, raphides, small circular 

 crystals, and crystal sand. 



From the result of this investigation it would appear, 

 that each of the above is restricted to a particular organ 

 of the plant, such as leaves, bark, root and timber, but in 

 the case of the latter only ordinary solitary crystals were 

 found, which seems to prove that this is the usual form for 

 wood structure. 



In the timbers examined to illustrate this paper, the 

 crystals were so numerous that sufficient definition was 



1 This Society, 1905, Vol. xxxix, pp. 23 to 32. 



