512 



JOURNAL OF ECONOMIC ENTOIMOLOGY 



\yo\. 8 



The Compromise Curve is well shown in the fifth curve. Here the 

 direction of the curve seems to be the result of two forces and might 

 easily occupy any one of a great range of positions according to the 

 relative power of the two influences. As shown in the diagram it is 

 very closely half way between the Acute curve above and the Stimu- 

 lation curve below. 



The Stimulation Curve represents a benign effect of cyanid. The 

 fact that there is such an action in the case of this chemical has al- 

 ready been pointed out.^ These curves show, in this case, that more 

 than half of the lots of eggs that would have failed to hatch under 

 normal circumstances have been made to hatch by the long continued 

 action of the cyanid. The beginning of this stimulative effect has the 

 same relation to the deviation line that the Acute curves show, and 

 the rate of stimulation is similar but in an opposite direction, suggest- 

 ing that the same causes are responsible in both cases. There must 

 be profound ph^^siological changes which are essential^ beneficent 

 but violently poisonous when carried to excess. 



The Critical Line represents a second evidently significant phj^si- 

 ological crisis, bearing the same quantitative relationships with the 

 concentration of the gas as the deviation line but with a greater time 

 factor, though quahtatively indentical. It measures the culmination 

 of the violent action of the poison and the beginning of the recovery. 

 Those not dead at this time have a fair chance of sur^dval. Perhaps 

 the production of antibodies pro\ddes for the reduction of the quantity 

 of poison within the body. 



The method of plotting the results of experiments of this kind should 

 be such that the irregularities at the two ends of the curves should be 

 approximatel}^ of equal magnitudes, for in this way one will give 

 proper weight to all the data. 



This was done in the present case, the time intervals being arranged 

 logarithmically. The fact that by this arrangement the deviation 

 and critical lines are straight indicates that in general the phenomenon 

 occurs in proportional rather than in consecutive intervals. 



The theory of toxicity which this study enables us to put forward 

 is (1) that there are three separate effects produced b}^ a poison de- 

 pending on its concentration; (2) that there is a line of deviation be- 

 yond which their characteristics become most evident; (3) that acute 

 poisoning reaches a crisis after which the rate of death rapidly declines, 

 and (4) that these phenomena exhibit a series of very definite mathe- 

 matical relationships. 



1 Science, Vol. xli, pp. 267-269. 



