1018 



SCIENCE. 



[N. S. Vol. XV. No. 391. 



and closely related forms for tlie same pur- 

 pose. The relationship between the chem- 

 ical constituents of certain groups of plants 

 cannot, of course, be so apparent as is the 

 morphological relationship, simply because 

 it cannot be determined by inspection 

 alone, as the latter can. If, therefore, our 

 knowledge of plant constituents were suf- 

 ficiently complete we could perhaps write 

 monographs classifying the different spe- 

 cies of plants according to their chemical 

 constituents, as well as we now write mono- 

 graphs based solely on morphology. The 

 same alkaloid is often found exclusively 

 in certain families of plants, but the same 

 family, and even the same species, often 

 contains one or more alkaloids which dif- 

 fer from each other by a few atoms of 

 hydrogen or a few simple organic radicals, 

 or they may differ only in being isomers or 

 polymers. In many of these cases one 

 compound can often be transformed into 

 another by a few simple reactions. 



Of the two great classes of plants— the 

 non-flowering and the flowering— the for- 

 mer contain very few active principles, and 

 those which do exist are far more simple 

 than those which are found in the flower- 

 ing plants. In the bacteria, to be sure, we 

 have highly developed poisonous com- 

 pounds, the toxalbumins, but aside from 

 these there are few active principles in 

 them. The simpler group of poisonous 

 acids is here more abimdant ; there are few 

 glucosides and still fewer alkaloids. The 

 most prominent of the latter are ergotine 

 from ergot, and muscarine from the fly 

 fungus (Amanita muscaria). There has 

 been an immense amoiint of study done on 

 the former but its chemical composition is 

 still in a most unsatisfactory condition. 

 Trimethylamine, one of the simplest of the 

 so-called alkaloids of the aliphatic series, 

 is also present in ergot at certain stages of 

 its growth. According to the definition of 

 all^raloids now commonly accepted, however, 



neither trimethylamine nor muscarine is an 

 alkaloid, this class being restricted to the 

 benzol or aromatic series of compounds. 

 Proceeding still higher in our grouping of 

 plants we find that there are but two con- 

 spicuous alkaloids, toxine and ephedrine, in 

 the lowest group of flowering plants, and 

 that, in the many families of the next 

 higher group, the monocotyledons, there is 

 but one family, the Melanthacese, which 

 contains more than one or two important 

 alkaloids. In the highest group, however, 

 there is a long list of alkaloids, arranged 

 often in groups, characteristic of the fam- 

 ily to which the plants belong. The atro- 

 pine-like alkaloids of the Solanacete; the 

 strychnine-like alkaloids of the Logania- 

 eeaa; the morphine-like alkaloids of the 

 Papaveraceae ; and the quinine-like alka- 

 loids of the Rubiaceffi are the best well- 

 known groups. There is a similar distribu- 

 tion of the glucosides throiighout the plant 

 kingdom, but these compounds, being 

 simpler than the alkaloids, are found lower 

 down in the plant scale. It is interesting 

 to note, however, that throughout the whole 

 list of the tremendously abundant family 

 of grasses, one of the lowest families of 

 flowering plants, there are but two gluco- 

 sides, neither of which is at all well known. 

 One of these is loliin, from the poison 

 darnel, Lolium temulentum, while the 

 other, setarian, was isolated from miUet so 

 recently as in 1899 by Professor E. F. 

 Ladd, chemist of the Agricultural Experi- 

 ment Station at Fargo, North Dakota. 

 The grouping of all plant constituents in 

 accordance with their plant classification 

 offers a tempting field of work, but this 

 cannot well be undertaken to advantage 

 until the identity and nature of a great 

 many more plant substances have been de- 

 termined. 



Sohn's 'Dictionary of the Active Prin- 

 ciples of Plants' enumerates about 600 sub- 

 stances, all of which are included under 



