1022 



SCIENCE. 



[N. 8. Vol. XV. No. 391. 



deiamte conclusions in regard to the devel-^ 

 opment of their poisons, or of their location 

 in the plant, but all druggists and phy- 

 sicians are aware that the chemical com- 

 pound by virtue of which a drug is of 

 therapeutic value is almost invariably more 

 abundant in one part of a plant than in 

 another. The same is true of all plant 

 compoimds. 'J'he variability of cultivated 

 drugs in their contents of active principles 

 was alluded to above. A more satisfac- 

 tory example of how artificial environment 

 can affect the chemical constituents of 

 plants may be found in a Bulletin recently 

 published by Dr. H. W. Wiley, Chief of 

 the Bureau of Chemistry of the Depart- 

 ment of Agriculture, and entitled 'The 

 Influence of Environment upon the Com- 

 position of the Sugar Beet.' In this bulle- 

 tin it is shown that the factors which deter- 

 mine the maximum yield of sugar are as 

 follows: high latitude, free use of fertil- 

 izers, and an even distribution of a rain- 

 fall of from three to four inches during the 

 months of May, June, July and August, 

 and a reduction of rainfall for September 

 •and October.' 



Natural environment affects some poi- 

 sonous plants in a similar way, but in this 

 case the more southerly plants are apt to 

 have a greater development of the active 

 constituents than those further north. This 

 is particularly noticeable in the Indian 

 hemp, Cannabis sativa. The plants of the 

 Southwest contain a larger quantity of the 

 active principles than the more northerly 

 ones do. A striking example of the pos- 

 sible diurnal variation of the amount of 

 ' poison in the leaves of plants is shown in 

 ■a very instructive investigation by Dr. J. 

 P. Lotsy of the cinchona plant. The 

 author showed that the quantity of alka- 

 loids varied greatly in the leaf as taken by 

 day or night and on sunshiny or cloudy 

 days, being most abundant in the first in- 

 stance in each case. He showed also that 



these alkaloids are formed in the leaves 

 during the day and are almost wholly de- 

 posited in the branches or bark at night. 

 If gathered in the early morning therefore 

 cinchona leaves would be practically inert, 

 while if gathered in the evening, especially 

 on a sunshiny day, they would be in their 

 most active condition. The foliage is, in gen- 

 eral, the part of a plant which causes most 

 eases of stock-poisoning. The period of 

 leaf maturity is regarded by some culti- 

 vators of medical plants as being the time 

 at which its chlorophyll content is most 

 highly developed, or when the leaves are 

 most intensely green. This is generally 

 soon after the flowering time in the case of 

 herbaceous plants, but with some, such as 

 the aconite, the purple larkspur and the 

 poison camas of Montana, and many bulb- 

 iferous plants closely related to the last, 

 it is earlier, the leaves of some of these hav- 

 ing commonly dried up before the plants 

 have flowered. In such cases the leaves 

 would naturally be most active physiologic- 

 ally if eaten before the plants blossom, and 

 might be practically inert at other times. 

 Such is probably the case with the purple 

 larkspur and death camas just referred to. 

 The active principles are sometimes found 

 most abundant in the most rapidly growing 

 parts of the plant, as in the white sprouts 

 of potatoes, and again they are to be found 

 in parts which have been fully developed, 

 as in the case of sapotoxin in the corn 

 cockle, Agrostemma githago. It has re- 

 cently been shown that in aconite seeds the 

 central parts contain most of the aconite, 

 while the seed coats are free from it. In 

 the calabar bean the very poisonous alka- 

 loid eserine is found in the cotyledons. In 

 the seeds of the common jimson weed and 

 black henbane the alkaloids are located 

 chiefly in the layer beneath the epidermis ; 

 the epidermis itself and the seed covering 

 of each are free from alkaloids. In jimson 

 weed the quantity of alkaloids in un- 



