made to maintain the temperature of the treated seed continuously 

 at about 55 C., the actual range of temperature during this time being 

 from 53-5 to 58 C. a difference of 4-5 C. only. 



From Table II it would seem that the optimum temperature for 

 this machine lies between 55 and 56 C., but that at all the 

 temperatures tried there seems to be a small percentage of worms that 

 succeed in surviving the treatment, together with a small percentage 

 of seed that is damaged. As a matter of fact the figures probably make 

 the case look considerably worse than it actually is. As far as the 

 worms are concerned, the number that would survive in practice 

 is probably less than one in a thousand. The samples examined were 

 taken as they came from the machine and placed in small bags in which 

 they cooled rapidly. In practice, however, the seed is sacked as it 

 comes from the machine and in the sacks remains hot for a long time, 

 during which the seeds which have come through the machine quickly, 

 and which have in consequence not attained the average temperature, 

 absorb heat from their neighbours and eventually reach a temperature 

 sufficient to kill the pink boll worms they contain. It follows, then, 

 that those worms which survive the passage through the machine 

 are almost certainly doomed to die after leaving the machine unless 

 chance brings them to the outside of the sacks. That this is so is 

 confirmed by the fact that six samples taken at random from the 

 treated sacks a week or two after the experiments did not contain a 

 single living worm between them. 



With regard to the loss in germination of the seed, the actual 

 existence of this in practice is somewhat doubtful. The seed treated 

 was very poor and very variable in quality and the differences in 

 germination recorded are within the range of experimental error. 

 Certainly the fact that the average of the controls is higher than the 

 average of any of the three series of treated seed shown in Table II 

 makes it appear probable that the damage is actual and not merely 

 apparent. Against this, however, one may put the fact that of the 

 three series of treated seed the one which shows the lowest germination 

 is the one which underwent the least severe treatment. The previous 

 experiments carried out with the machine also fail to confirm the 

 supposition that the seed is damaged, the seed treated on February 14 

 giving an average germination of 86 against a control of 88, while 

 that treated on March 23 gave an average of 67 against a control 



