Bitter Pit and Sensitivity to Poisons. 



231 



llie influence of tenipeidt nie . To tost tlie influence of tenipera- 

 turo on the sensitivity to jioisons, snowtiake potatoes were selected, 

 and nieri'Uiic rlildridt' used as \\\v poison. .MttT the i-einoval of 

 fragments of the skin ai'ound a median line, they were immersed 

 for '.\ days in half a litre of solution. After the exposure they 

 were cut in half througii this line, and exposed t«> the air for 

 a couple of hours. At .■{(»<> ('., even if the lii[uid is kejit well 

 .aerated, the immersal cannot he ))rolonged further, since after 

 the third day the controls in puie water, which previously are 

 unaffected, begin to .show signs of asphyxiation, dead, discoloured 

 tissue then appearing, usually fii'st at the centre. In a 1 per 

 1,000,000 solution at 30O C. bacteria develop rapidly in spite of all 

 precautions, and hence the solution was replaced by fresh sterile 

 solution daily. With the 1 in 10,000 and 1 in 100, OOO solution at 

 30 C, most of the pits were pale at the surface, with a curved 

 dark band deeper in, and on exposure to aii- in mo.st cases a more 

 diffu.se and less darkened zone of dead tissue extended a short 

 distance into the pulp beyond this band. With shorter periods 

 of immersal, the poisoning does riot extend beyond the dark band. 



SENSITIVITY OF APPLE AND PO'J'ATO (Poison Limit 

 at 13-15=C.) 



