ELLINOR HELENE BEHRE. 



pairs of lots. In no. I for example, the control lot brought 

 from high to low temperature at the time of susceptibility deter- 

 mination shows a susceptibility greater than that of the experi- 

 mental lot which has been 12 hours at the low temperature 

 before the susceptibility determination. 



Of these twenty- two cases almost 73 per cent, show that 12 

 hours in a lower temperature than the living one before the addi- 

 tion of cyanide makes the worms more susceptible to cyanide 

 than those which have been subjected to the depressing influence 

 of the cold and of the cyanide simultaneously; in other words, 

 the worms first brought into low temperature then subjected 

 to cyanide die faster than those brought into low temperature 

 and cyanide at the same time. Judging from these data a 12 

 hours' subjection to a lower temperature produces some degree of 

 adjustment; in most cases the worms have apparently under- 

 gone some increase in metabolic rate during the twelve hours at 

 the lower temperature. Just what the nature of this adjustment 

 is had better be considered later when there are more data from 

 which to judge. But that it is not merely a shock effect is 

 evident from a comparison of the effects of acclimation periods 

 of various lengths. In 12 hours the worms show less acclimation 

 than in 36 hours, and in that period less than in three days, so 

 that evidently the process is not ended in a period shorter than 

 three days, which itself is surely too long a time for shock effect 

 from a change of 10 to persist. The process then is gradual, 

 covering a considerable period of time, which may range from 

 three days to one week, by which time the acclimation is fairly 

 complete and the new rate established. 



The possible sources of error in these experiments account for 

 most of the exceptional results quite readily. The series tested 

 at low temperature all take so long even to begin disintegration 

 that some degree of acclimation undoubtedly occurs in the 

 period before death begins, which would bring the two lots very 

 nearly to the same rate. This might well explain the inconsis- 

 tency in no. 14, where a relation like the majority held until 

 the last half hour at which time the condition became reversed. 

 The fact that the series were not followed up to complete dis- 

 integration may explain the result of nos. 4 and 13. The worms 



