54 MANUAL OF POISONOUS PLANTS 



"In the study of this question it is important to remember the possible 

 diversity of origin of this body, and every cyanogenetic plant will be required 

 to be examined on the lines laid down by Treub." 



The wide distribution of glucosides that yield hydrocyanic acid is evident 

 from the list above. Dunstan and Henry ^ discovered three glucosides, dhurrin 

 Cj^jHj^O^N in the common sorghum, lotusin C^gH^j^Oj^gN in a species of 

 lotus of Egypt and phaseo-lunatin Cj^(,H^^OgN in wild beans of Phaseolus 

 lunatus, the common lima bean. Brunnich ^ attributed death from the feeding of 

 immature sorghum to dhurrin. Power and Lees ^ isolated from the seeds of 

 Gynocardata odorata a glucoside to which they gave the name gynocardin 

 Cj.^Hj^gOgN. AH of the above glucosides yield on hydrolysis, hydrocyanic acid. 

 The most important and best known of all the glucosides that yield hydro- 

 cyanic acid is amygdalin. 



Greshoff discovered an amygdalin-like glucoside in two tropical trees, 

 Pygeiim parviflorum and P. latifoUum. The same author found glucosides. 

 in a member of the milkweed family Asclepidaceae. The Pangium edule of the 

 tropics contains a large quantity of a glucoside capable of being converted into 

 hydrocyanic acid and a large amount can be prepared from a single plant. The 

 Hydnocarpus inebrians also contains a large quantity of a glucoside which 

 yields hydrocyanic acid. It is used to destroy fish. The common linseed cake 

 contains a glucoside which yields prussic acid, Francis found prussic acid in 

 the sweet cassava root, .0168 per cent, and in the bitter cassava .0275 per cent. 

 It is well known that fresh bitter cassava root is bitter poison. The above 

 facts are brought together by Blyth in his work on poisons and may be con- 

 sulted for more of the details. 



The statistics on poisoning seem to indicate that it occupies third place 

 among poisons in the order of frequency in Great Britain. In that country 

 there are about forty deaths annually from this poison according to Blyth. It 

 is responsible for the loss of a great many cattle in sections of the country 

 where the wild cherries are abundant and also from sorghum poisoning. It 

 is frequently used for criminal poisoning, at one time more frequently than now. 

 It is nearly always taken by the mouth into the stomach, but occasionally the 

 vapors produce death. It is generally used by Entomologists to kill insects. 



Blyth gives the symptoms of poisoning as follows : Cold blooded animals 

 require a larger relative dose than warm blooded animals except the birds 

 which are slightly less sensitive but the action is essentially the same. Hydro- 

 cyanic acid acts in two ways : 



1. It profoundly interferes in the ordinary metabolic changes in animals. 

 2. It causes a paralysis of the nerve centers. 



Normal blood decomposes with great ease hydrogen peroxide into oxygen and water. 

 If it is normal venus blood and a little hydrogen is added it becomes bright red, but if a 

 trace of prussic acid be present it is a dark brown dolor. 



The blood corpuscles lose their power of conveying oxygen to all parts 

 of the system and asphyxia results. The main symptoms in animals are as fol- 

 lows: 



The main differences between the symptoms induced in cold-blooded and warm-blooded 

 animals, by a fatal dose of hydric cyanide, are as follows: 



The respiration in frogs is at first somewhat dyspnoeic, then much slowed, and at length 

 it ceases. The heart, at first slowed, later contracts irregularly, and at length gradually 



1 Proc. Roy. Soc. Ixviii and Ixxii (See Blyth "Poisons" p. 204). 



2 lb., Ixxxiii. (See Blyth "Poisons" p. 204). 



3 Journ. Cham. Soc. Ixxxix. (See Blyth "Poisons" p. 204). 



