368 



SCIENCE 



[N. S. Vol. XLI. No. 1053 



PEBCENTAGE OF HATCH 



European Fruit Scale on Christmas Berry 



Concentrations 

 64 32 16 



54.30, 52.20, 50.10, 48.50, 48.01, 46.51 and 43.30, 

 respectively. 



In all such experiments individual varia- 

 tion will be very pronounced, but averages 

 based on as large a number of series as this 

 are quite dependable, and we can safely say 

 that long continued action of cyanide at a 

 strength below that producing fatal results 

 exerts on the contrary a benign influence. 



It will be remembered that fatal results fol- 

 low, as a rule, from weaker doses when the 

 time of exposure is long, but far short of the 

 theoretical proportion that would follow on 

 the assumption that the toxicity was depend- 

 ent on the amount of gas absorbed and that 

 this varied directly as the time and density. 



The possible explanation used on the as- 

 sumption of the production of antibodies 

 within the egg can only partially, if at all, ac- 

 count for the facts since another phenomenon, 

 the acceleration of the rate of development 

 resulting in an earlier hatching, is also evi- 

 dent. 



The quickened oeU activities indicate that 

 the effect of cyanide, at least in light doses, 

 is to increase cell permeability, a process of 

 rejuvenescence which may be specially useful 

 in an insect's egg so full of yolk material. 

 Decreased permeability is generally consid- 

 ered the measure of approaching death, but it 

 may be that acute poisons like the strong in- 



secticides produce a violent death of cells by 

 the sudden or excessive increase in catabolism. 



A third suggestion which may seem rather 

 bold to offer in the case of animal tissue is 

 the possibility of the nitrogen of hydrocyanic 

 acid being available as food directly utilizable 

 by the protoplasm of the cells. The basis for 

 this suggestion is the fact that in a series of 

 experiments by Mr. E. Ralph Ong, conducted 

 in my laboratory with seeds in hydrocyanic 

 acid solutions, a very remarkable and similar 

 acceleration in time of sprouting was observ- 

 able when the solution was slightly short of a 

 toxic strength, and these plants developed 

 with all the appearance of having had a strong 

 nitrogen fertilization. There is no doubt of 

 the ability of plant tissue to utilize ni- 

 trogen in various forms, and we know of no 

 special mechanism necessary to accomplish 

 this which is characteristic of vegetable proto- 

 plasm. 



The cyanide produced from hydrocyanic 

 acid absorbed in the tissue of a scale-insect 

 egg when not immediately fatal, but present 

 in considerable quantities may be either util- 

 ized as food or act as a disturber of the 

 equilibrium of cell permeability or both and in 

 addition it may cause a reaction bringing about 

 the production of 'antibodies which will neu- 

 tralize the poison. One or more of these fac- 

 tors may produce a degree of immunity from 



