Hitter Fit in Ajyplet>. 4^^ 



tlu' stattli LTrains is jn-fseiit during ar K'ust tlir early stages of 

 liitter {'il. 'J'lu' starch grains are iionnal and capable of solution. 

 Tht.' only agency capable of preventing their solution in localised 

 living cells under the conditions existing is a poison. 



The most resistant apple (Yates' Pippin) to poison ii^ also the 

 most resistant to bitter pit. 



At low temperatures the resistance to poison is increased ten tj^ 

 fi hundred times (0 deg. C. as compared with 30 deg. C). In cool 

 storage the resistance to the full development of bitter pit is- 

 fcimilarlv increased. 



'riie poisoning theory is in accordance with all that is known 

 in regard to the sensitivity of the pulp cells to poisons, to their 

 diminishing resistance with increasing age, and to the changes 

 which take place in the cell. The increased percentage of ash in 

 bitter tissue is evidence pointing in the same direction. 



Dr. White, in bitter pit apples from an orchard heavily sprayed 

 with arsenate of lead, was able to detect the presence of traces of 

 lead. Against this is the fact that the State Analyst was unable to 

 detect arsenic in a limited number of bitter pit apples from four 

 orchards certified to have been unsprayed. Anjr poison is, however, 

 capable of producing bitter pit symptoms, and the results obtained 

 by the Federal Analyst show that it is possible to poison the pulp 

 cells of apples by traces of poison so minute as to be incajjable of 

 det€ctiori even by delicate chemical analysis. 



No other theory of bitter pit will stand critical examination or 

 8cientific testing. Mr. McAlpine's vascular interruption theory is 

 unsupported by observation or experiment, and is negatived by the 

 fact that during the early stages of bitter pit the vascular connec- 

 tions are normal. The cracks appearing in the tissue form during 

 the later stages, they are not always present, and are the result 

 and not the cause of the death and contraction of the pulp cells. 

 In addition, the starch grains of bitter pit tissue and its ash con- 

 .stituents are carried to it by materials conveyed along the vascular 

 bundles, and since the percentage of ash in bitter pit tissue is higher 

 than in healthy ptilp, the conducting channels must have been func- 

 tioning more actively if anything than usual. The accumulation of 

 absorbed poisons at certain points causes these cells to be sacrificed 

 to maintain life in the rest. 



The browning of apple pulp is due to the oxidation of tannic acid. 

 Apparently gallotannic acid occurs in numerous minute rounded 

 vacuoles in the protoplasm of the pulp cells in addition to the iron- 

 greening tannin of the cell-sap. If so, the plasmatic membranes of 

 these vacuoles nuist be impermeable to alkali or oxygen, or both when 



