June 27, 1902.] 



SCIENCE. 



1017 



constantly looking at these problems from 

 both points of view could not well be 

 thrown into intimate touch with the sub- 

 ject long before many interesting problems 

 would be presented to him for solution. 

 When once conceived these problems are 

 readily susceptible of treatment, either by 

 the chemist or the physiologist alone, or by 

 one or both of them in conjunction with 

 the botanist, the biologist or the pharma- 

 cologist. It was with the object of inter- 

 esting you, as chemists, in this line of work 

 that I was induced to select it as the sub- 

 ject of my discourse on this occasion. No 

 more interesting and self-sufficient life- 

 work could possiblybe suggested to a young 

 student starting on his college career than 

 the investigation of plant poisons. As 

 fascinating as a game of chess, the work 

 calJs forth, for its most successful treat- 

 ment, the widest activities of mind and the 

 most skillful handling of finely adjusted 

 instruments. Art and literature lend a 

 peculiar charm to the work, while the warm 

 plaudits of men await him who solves any 

 of the important chemical problems of im- 

 munity. This inviting field comes, I main- 

 tain, as properly within the scope of plant 

 chemistry as within that of medicine, for 

 disease is simply a disturbance of the nat- 

 ural functions of the animal economy, 

 caused by poisons, many of which are ex- 

 creted within the affected animal by such 

 low plant organisms as bacteria and per- 

 haps molds. Indeed it has been shown 

 that all of the lesions supposed to be caused 

 by certain living bacteria can be produced 

 by the administration of sterilized filtrates, 

 obtained by passing extracts made from the 

 bacteria through a Pasteur filter. 



Plant poisons divide themselves most 

 naturally and most comprehensively ac- 

 cording to their plant origin; all attempts 

 at a chemical classification have been in- 

 complete because of our ignorance of the 

 composition and structure of many of the 



compounds, while the physiological classi- 

 fication is unsatisfactory on account of our 

 ignorance of the chemical composition of 

 the compounds and of their exact mode of 

 action on animal life. Let us inquire into 

 the nature of the parallelism which exists 

 in the grouping of plant poisons, and the 

 grouping of the plants which contain them ! 

 Plants are commonly divided into spe- 

 cies, genera and families, and these are 

 grouped into two series— the flowering and 

 the non-flowering plants— the latter being 

 the more simple morphologically. Each of 

 these in turn is grouped into smaller class- 

 es. Proceeding from the more simple to 

 the more complex, we have in the non- 

 flowering plants such groups as the bac- 

 teria, the diatomSj the molds, the fleshy 

 fungi, the mosses and the ferns, while in 

 the flowering plants we have the monocoty- 

 ledons with parallel-veined leaves and the 

 dicotyledons with net-veined leaves. This 

 classification is, in general, based on the 

 general morphology of the plant, but in the 

 lower orders, especially in the bacteria, the 

 chemical composition or at least the chem- 

 ical and physiological reactions which the 

 plant is able to induce are taken into con- 

 sideration in the differentiation of the spe- 

 cies. In many of the subdivisions in the 

 higher groups, however, there is often an 

 apparent chemical basis for classification. 

 It seems just as reasonable to suppose, as 

 van Rijn has shown in his book entitled 

 'Die Glykoside,' that there should be gen- 

 etic relationships between the chemical sub- 

 stances represented in any one group of 

 plants, as that there should be morpho- 

 logical relationships. Both results are 

 brought about entirely by the energy of 

 the living cell, a process which is undoubt- 

 edly largely chemical in its character, and 

 would seem almost as necessary for a plant 

 to gradually evolve new and therefore 

 closely related chemicals for slight changes 

 in environment, as that it should evolve new 



