20 Alfred J. Ewart : 



Time of Inimersal in Chloroform. 

 Temperature !•> seconds 10<^ seconds 1000 seconds 



0°C-1°C. - Several shallow - As before but pits - General browning- 



pitsiipto5mm. slightly uiore over whole sur- 



diaiueter and numerous. face from \ to- 



1 mm. depth. 2 mm. deep. 



14°C-15°C. - Several sunken - Numerous, larger - General brownings 



pitsuptoSmm. and more deeply over whole sur- 



diameter and sunken pits up to face from 2 to 



2 mm. total 3 mm. depth, 8 mm. deep, 

 depth. partly confluent. 



In this case the same amount of poison enters in each pair of 

 apples subsequently kept at different temperatures, but the poison- 

 ing action is less at the lower than at the higher temperature. 



he poisonous action of cell contents and cell 

 products. 



It has been suggested that the escape of the cell contents either by 

 bursting or by exudation might cause the poisoning of neighbour- 

 ing cells and the formation of bitter pit. Against this is the fact 

 that young apples may be punctured without any result beyond the- 

 production of a superficial scar or depression when adult, but it 

 seemed advisable to test the influence of the expressed sap and of 

 different cell products on living pulp cells. 



The injliiencf of expressed sap on prepnred apples. 



The sap was rapidly expressed by pressure, and sound prepared 

 apples floated in pure sap, in 20 cc. of sap to 80 water, and in 2 cc. 

 of sap to 98 water for two days. They were immediately examined 

 and also after five days in air, but no signs of poisoning was shown 

 on any of the prepared spots, either using Yates' sap on Yates' 

 apple, Sturmer sap on Sturmer apple, or Yates' sap on Sturmer 

 apple, or Sturmer sap on Yates' apple. 



After two days the liquid develops micro-organisms, and after 

 three-four days' inunersal, superficial browning may he shown. 

 If the sap is boiled, sterilised vessels used, and the apples coated' 

 uith paraffin before preparing for inunersal, the expressed sap may 

 remain practically sterile for three or four days, and no signs of 

 poisoning were then shown in this time on any of the prepared 

 spots. Evidently, therefore, the unaltered sap of apples is not 

 poisonous to the pulp cells wlien applied to them externally. 

 Apparently the ectoplasmic membrane of the pulp cells has the same- 

 diosmotic relationships to the vacuolar contents as the vacuolar 



