4 o 



ON THE POISONOUS ACTION OF DI-CYANOGEN. 



Only in one case, where the turnip seeds had remained in the 

 hydrocyanic acid solution, the development of the cotyledons 

 was observed after 6 days while the life of the root-germ was 

 entirely destroyed. Here probably the hydrocyanic acid did not 

 enter far enough into the seeds to kill all the cells, while the 

 root-germs were more exposed. 



Action of Di-cyanogen and Prussic Acid 

 upon Lower Aquatic Animals. 



When under the microscope infusoria, nematodes, rotatoria, 

 annelides, Copepodes, and Ostracodes were brought into contact 

 with several drops of dicyanogen-solution in a dilution of 

 i : 2000, all the life was annihilated within two minutes, while 

 in a parallel experiment with an equal dilution of CNH the 

 animals were alive after 30 minutes, but some time afterwards 

 died under convulsions 1 ). In di-cyanogen solution of 1 : 10000 

 (200 c. c.) the death of these animals very soon took place, also; 

 only the worms lived longer, but after 15 hours they also died. 

 In hydrocyanic acid of the same dilution the animals lived 

 longer than in the cyanogen solution, and still after 15 hours 

 ostracodes showed convulsions in their legs. Even in the dilu- 

 tion of 1 : 100000 of dicyanogen all infusoria with the excep- 

 tion of some monadines were killed. Also the copepodes died, 

 but the ostracodes and worms still showed convulsions. In 

 hydrocyanic acid of the same dilution many infusoria were 

 alive after 5 hours, and some even after 18 hours. In a second 

 experiment with some mud rich in infusoria (Paramaecium) 

 some individuals were found alive after one hour in cyanogen 

 solution of 1 : 20000, but all were killed after 20 hours even in 

 the solution of 1 : 100000, while in the case of hydrocyanic acid 

 in the same dilution many infusoria were left alive. 



We see, therefore, that all these experiments prove the di-cy- 

 anogen to be a stronger poison than hydrocyanic acid ; and, 

 therefore, the results of B. Bunged with vertebrate animals, that 



1) The assertion of Schaer (Zeit. f. Biol. 1870, Bd 6, S. 511), that infusoria are 

 not killed by HCN is certainly erroneous. It may be that only an experiment of 

 short duration under the microscope had been made. In our experiments with 

 infusoria ordinary well-water was used for the dilutions. 



2) According to B. Bunge (Arch f. exper. Path., Bd. 12, S. 41-75, or, Jahresb. 

 f. Anat. & Physiol., 1879, Bd. 8., Ab. 2, S, 187), small doses of cyanogen produce 

 general central paralysis. With warm blooded animals dyspnoe, and paralysis of 

 respiration are produced. For killing a cat 0.02 grm. cyanogen are necessary while 

 of prussic acid 0.004 g rm - suffice. 



