324 True and Hunkelj The Poisonous Effect Exerted etc. 



Table X. 



Electrical Conductivity of Hydroquinone (Bader). 



V. liiy 100 k. 



11,6 0,15 0,0000016 



23,2 0,26 0,0000024 



46,4 0,58 0,0000059 



92,8 1,94 0,0000260 



1.100 = 356. K = •? 



Electrolytic dissociation can hardly play any iinportant pari 

 in determining the toxic action of hydroquinone Solutions, The 

 Solutions of this substance in the course of a very few hours turned 

 to a dark cinnamon brown. They were hardly to be regarded 

 as Solutions of hydroquinone in view of the ease with which this 

 substance is oxidized. *) Fresh Solutions were used and kept in 

 the dark except when the lupines were under Observation. Even 

 then the Solutions became strongly discolored. The toxic value 

 of this discolored Solution is 1/600 gram-molecule of the original 

 hydroquinone per liter or perhaps even more dilute. The results 

 here obtained could hardly be regarded as due to the phenol 

 itself, and the toxic value of hydroquinone unchanged we do not 

 know. A large number of experiments with Spirogyra were 

 performed, and some very interesting results were obtained. ^) 

 It seemed that before color changes set in, hydroquinone Solutions 

 are not much more poisonous than phenol toward this alga. As, 

 however, the color of the Solution deepened, the poisonous action 

 increased in intensity. Solutions were exposed to light and air 

 in the hope of obtaining a stable Solution. After several days, 

 the action on Spirogyra was again tested with rather surprising 

 results. The toxicity had increased to a great degree, and the 

 first concentration in which a majority of the filaments of the 

 alga were found to be able to respond to plasmolysing agents 

 was 1/25600 gram-molecule calculated ou the hydroquinone origi- 

 nally contained. 



Some experiments conducted by Mr. W. D. Frost, Assistant 

 in Bacteriology at the University of Wisconsin, and by Mr. 

 Robert Gay, a Student of the same Institution, showed that 

 this discolored Solution had a strong antiseptic action, vegetative 

 cells of Staphylococcus pyogenes aureus being in great part killed 

 or rendered incapable of growth when exposed for thirty minutes 

 to a Solution containing 1/1500 gram-molecule of hydroquinone 

 per liter. This phase of the action of this Compound is now 

 under study, 



It was thüugt that possibly a like treatment of Solutions of 

 the stabler phenols might show somewhat analogous though 

 perhaps less striking results. Accordingly, a Solution of phenol 



^) Schmidt, E., Ausführliches Pharmaceutisches Lehrbuch der Chemie. 

 3. Aufl. Band II. p. 942. 



'^) True, K. H., Algae and Antiseptics. (Pharm. Review. XV. 189 7. 

 p. 152.) 



