886 



The work of Dr. Syme was repeated, gasoline being used as the extractive material in preference 

 to ether, which Syme used. Chips of limbs were used in one experiment, while leaves were used in another. 

 In the summary the author states that " natural glucoside of fisetin, rhamnose and gallic acid is non-toxic," 

 and " there is not sufficient evidence that a poisonous substance which Syme attempted to decompose was 

 not a complex containing a poisonous body and one or more non-toxic glucosides in addition." (J. B. 

 McNair, in Journ. Amer. Chem. Soc., xxxviii, 1417, 1916.) 



2. " On the Constituents of Poison Ivy." — Dr. Syme worked on the ether extract of the leaves and 

 flowers of one species, while McNair worked on the gasoline extract of the limbs of the other species under 

 discussion, and secured different results. He therefore concludes that Syme's work is wrong. The only 

 other comment to be added is that McNair may not have given sufficient weight to the well-known fact 

 that the botanical differences may often be detected only with difficulty, whereas the chemical difference 

 may differ widely. This phase of the work has been discussed a number of times, especially by Schorger. 

 Then it was shown that lavender, fennel, &c, produce different oils when grown under different climatic 

 and soil conditions. Also that the distillate of the wood of certain pine-trees differs decidedly from that 

 of the leaves and twigs, so that it would be dangerous to assume that the poison occurring in the leaves 

 and flowers of Rhus toxicodendron should be found in the bodywood of this plant, and certainly it would be 

 inadmissible to assume that this same poison, or the same non-toxic constituents should be found in the 

 limbs of an entirely different species, R. diversiloba." (S. F. Acree, junior, in Journ. Amer. Chem. Soc., 

 xxxviii, 1421, 1916). 



"... An instance of this kind has been observed in the case of the so-called ' Bastard Logwood ' 

 of Jamaica. The botanical characteristics of this are almost identical with those of the common logwood, 

 but its physiological properties are so different that it is worthless for commercial purposes." (Sir D. 

 Morris, Pres. Address, Brit. Assoc. (Botany), 1919.) 



" ' Bastard Logwood ' has a much lighter-coloured heartwood, yielding little or no dye. There are 

 no characters of leaf or flower which distinguish it from the true Logwood. It may be considered a physio- 

 logical species, and trees should be destroyed wherever found." (Bull. Torrey. Bot. Club, xxxi, 367, quoted 

 by Fawcett and Rendle in " Flora of Jamaica," iv, 97.) 



Perhaps it may be that further investigation will ascertain that the botanical 

 characteristics " almost " identical with those of the common Logwood (Hwmatoxylon 

 Campechianum) , will prove to be fundamental, and others may be found, and these, 

 taken with the physiological properties, may settle the point that the two trees are 

 not identical species. 



At the same time we have undoubted cases of variation of chemical con- 

 stituents in the same species. I give two examples additional to those cited by me 

 at Part VIII, p. 248. See also Acree's paper, just quoted. 



1. " Toxic Principles Affected by Cultivation." — " It is generally recognised that plants which, in 

 the wild state, contain poisonous substances of a nitrogenous character, tend, under the influence of culti- 

 vation, to contain a smaller amount of these toxic principles. Comes, for example, has stated that if a 

 plant which, in its wild state, was of therapeutic value, be cultivated for several generations on manured 

 and irrigated soil, it becomes in time quite useless, owing to the disappearance of the active principles. 

 A familiar example is afforded by the Almond, the prussic acid-forming glucoside of which, always present 

 in bitter Almonds, has disappeared from the cultivated sweet Almond. Conflicting statements have been 

 made of latf. } > ars its to the toxicity of different varieties of Phaseolus Beans, some of which have been 

 proved to contain prussic acid in the form of a glucoside. Recently Messrs. Scurti and Tommasi, of the 

 Rome Agricultural Chemical Experiment Station, have determined the effect of nitrogenous fertilisers on 

 Phaseolus vulgaris and P. multiflorvs, collecting and analysing the seeds in each case. Particular attention 

 was directed to the amount of non-protein nitrogen, which is taken as a measure of the toxic principle. 

 The results conclusively show the presence of a larger proportion of non-protein in the beans from the 

 unmanured plants. The application of sodium nitrate, for example, reduces the amount of toxic nitrogen 

 in the seeds to about one-third of that present in the seeds of similar plants grown on unmanured soil." 

 Gardeners' Chronicle, 28th October, 1911. p. 307.) 



