June y7, 1902.] 



SCIENCE. 



1019 



the three commonly recognized classes 

 of these bodies, viz., the glucosides, tlie 

 amaroids or so-called bitter principles, and 

 the alkaloids. These three classes do not, 

 however, include all of the groups of toxic 

 substances which are represented in plants. 

 In addition there are mineral substances, 

 which under certain conditions may be 

 taken up by plants, acids, oils, enzymes and 

 their closely related congeners — the toxal- 

 bumins. 



Mineral substances very rarely cause 

 poisoning on account of their occurrence in 

 plants, but it has been shown that the pres- 

 ence of lead in a certain grass has led to 

 distinct symptoms of lead poisoning in cows 

 that ate it. An exceedingly important 

 pro])] em suggests itself in this connection 

 and that is the possibility of poisoning from 

 the gradually increasing use of insecticides 

 on fruit trees and on vegetables. It has 

 already been pointed out that plants which 

 have been manured with superphosphates, 

 which frequently contain arsenic, may ab- 

 sorb arsenic into their tissues to such an 

 extent that arsenic poisoning may result 

 from eating them. 



The great toxicity of prussic acid is well 

 known. It occurs free in certain plants 

 and in the form of a ghicoside in several 

 others, especially in those belonging to the 

 rose and apple families. Oxalic acid is 

 also present in the form of an acid oxalate 

 in many plants. It is extremely poison- 

 ous. Crotonoleie acid, from C rot on tig- 

 lium, is still more poisonous, the fatal dose 

 being represented by only .38 of a milli- 

 gram per Irilogram of body weight. 

 Poisonous acids are not so generally looked 

 for in i^lants as they should be, and it is 

 quite possible that the active principles of 

 some plants, the chemical nature of which 

 is still imknown, are acids. The effect of 

 the common loeoweed of the Western 

 States, Astragalus mollissimus, has been at- 

 tribiited to loco acid. 



The medicinal and therapeutic effects of 

 the vegetable oils are tolerably well linown, 

 but it is not commonly recognized that 

 some are poisonous. Among the most 

 powerful of these are the oils of chamomile, 

 cloves, cinnamon, sassafras, savine, rue, 

 hedeoma, and tansy. Jilany of these are 

 commonly used as flavor and to preserve 

 food, but it is certain that their excessive 

 use might result in serious gastric disorders 

 if not in death. All are useful on account 

 of their being antiseptic, a property which 

 was commonly recognized centuries ago by 

 the Egyptians in embalming bodies. Nut- 

 megs contain a volatile oil which is toxic; 

 two of the nuts proved fatal to a young 

 girl who ate them. The extreme toxicity 

 of toxieodendrol, the non- volatile oil of the 

 common poison ivy, Rhus radicans, and 

 poison sumach, Ehus venenata, has recently 

 been shown by Dr. Franz Pfaff, of the 

 Harvard Medical School, who proved tha.t 

 tJie hundredth part of a milligram easily 

 caused a severe dermatitis on many per- 

 sons, while as little as the thousandth part 

 of a milligram caused severe itching of the 

 skin and half a dozen vesicles on some per- 

 sons, and localized osdema on others that 

 were more sensitive to its effects. 



The glucosides are well known. One of 

 tJie most poisonous representatives of the 

 group is the active principle antiarin, from 

 the East Indian tree so well known to 

 legendary history as 'the deadly upas. ' Its 

 juice has been used in times of war by 

 savage tribes to envenom their arrows. It 

 takes but one to two milligi*ams of this glu- 

 coside to kill a moderate-sized dog in nine 

 minutes. Frogs are killed with a hun- 

 dredth of a milligram in twenty-four 

 hours. The results of a most interesting 

 investigation on the poisonous constituent 

 of a leguminous plant of Eg3T)t, known 

 botanically as Lotus arahicus, have been 

 recently published by two English investi- 

 gators, JMessrs. Dunstan and Henry. Its 



