36 



ON THE POISONOUS ACTION OF DI-CYANOGEN. 



ment of bacterial vegetation was seen in the control flask, while 

 in the flask of hydrocyanic acid solution a slight incipient 

 turbidity indicated a beginning of vegetation, and in tbe case 

 of cyanogen the liquid remained entirely clear and unchanged. 

 Several other experiments have been made in a dilution of i : 5000 

 and 1:3000, and in each case the poisonous action of the two 

 substances upon bacteria was clearly observed. 



In another experiment, 1 gram of peptone was dissolved at 

 ordinary temperature in 100 c.c. of a 1 : 1000 solution of hydro- 

 cyanic acid. After filtration, it was infected from putrid meat. 

 At the same time, 1% solution of peptone was infected from the 

 same source. After standing five days the latter solution showed 

 a putrid smell, and white flocculent masses consisting of numer- 

 ous bacteria, while in the first case no trace of turbidity or of 

 putrid smell could be observed and no bacteria were found on 

 examining under a microscope. 



In a further experiment, 1 : 1000 solutions of di-cyanogen and 

 hydrocyanic acid containing 1% of kreatin, 0.1% of di-potassium 

 phosphate and a drop of a 10% solution of magnesium sulphate 

 were infected from a vegetable matter in lactic fermentation. 

 After standing a fortnight in closed vessels at ordinary temper- 

 ature, these liquids 1 ) were perfectly clear and free from bac- 

 teria, 2) while the control solution showed a strong development. 



The poisonous action of hydrocyanic acid for bacteria was 

 also proved by the observation of Liebig, 3 ' that blood does not 

 undergo putrefaction for a considerable time, when 1/1000 of its 

 weight hydrocyanic acid is added. He also observed, that yeast- 

 water did not putrefy when some hydrocyanic acid was added 

 to it. 



Action of Di-cyanogen and Hydrocyanic Acid 

 upon yeast Cells. 



Some thick yeast 4 ' obtained fresh from a brewery was 

 mixed with a di-cyanogen solution of 1 : 2500 and after frequent 



1) At that time the di-cyanogen and prussic acid remained unchanged and were 

 perceptible by smell. 



2) According to E Schaer the development of mould fungi can be prevented by 

 hydrocyanic acid in a dilution of i : ioooo (Zeit. f. Biologie 1870, Bd. 6, S. 509.) 



3) Ann. der Chemie u. Pharmacie 1870, Bd. 153, S. 137 etc. 



4) The yeast-mass of the size of a pea corresponding to in average 0.07 — 0.1 grams 

 dry matter was shaken with 50 c.c. of the solution. 



