176 C. M. CHILD 



In spite of the earlier beginning and the more rapid progress of 

 disintegration the temperature difference is perfectly clear. Dis- 

 integration begins in Lot 1 after one and one-half hours : in Lot 2 

 at a temperature 5° lower it begins after two and one-half hours. 

 All the worms of Lot 1 reach Stage V within three and one-half 

 hours, while those of Lot 2 require five and one-half hours. In 

 short, the length of time to the beginning of disintegration and 

 to complete death (Stage V) at the lower temperature is almost 

 twice that at the higher temperature. Differences in resistance 

 resulting from differences in the coefficient of distribution would 

 be scarcely appreciable with a temperature interval of only 5°, 

 but the observed differences in resistance are almost 100 per 

 cent. Manifestly they must be due to some other factor. 



It is of interest to note that the differences in resistance in 

 both of the above series are of the same order of magnitude as the 

 usual temperature coefficient of chemical reaction for the tempera- 

 ture intervals used. 



The following KCN series with a temperature interval of 13° to 

 15° gives essentially the same results. 



Series 521 II. The worms used had been kept for three months 

 at low temperature: during the first month it fell from 10° to 

 5°C. and ranged between 4° and 5° during the following two 

 months. From this stock worms 16 to 18 mm. in length were 

 taken for the test. Lot 1, ten worms, was placed at a tempera- 

 ture of 20° for twenty-four hours and then brought into KCN 

 0.001 m. Lot 2 was kept at 5° in KCN 0.001 m. The tempera- 

 ture interval is then 15°. 



Worms in KCN 0.001 m. 10.30 a.m., March 20, 1912. Table 

 5 gives hourly observations. 



The difference in resistance is striking. After two and one-half 

 hours four worms of Lot 1 have begun to disintegrate, but Lot 

 2 does not reach this condition until after ten and one-half hours, 

 i.e., a little over four times as long.^ Lot 1 reaches Stage V 



1 Owing to the fact that observations were made only once an hour in this series, 

 the earliest traces of disintegration in Lot 1 were not observed. They probably 

 occurred about two hours after the worms were placed in KCN, but no record is 

 made until two and one-half hours. On the other hand, in Lot 2, where disinte- 

 gration proceeds much more slowly, the earliest traces are recorded at seven and 



