Bitter Pit in Apples. 413 



Reduction of 

 Fehling's. 



Slight 

 Slight 

 Very faint 

 Very faint 



Distinct traces of diastase were present in all four cases, 

 and although the amount is small, it is impossible that the 

 starch grains could have remained for 10 weeks without any 

 signs of corrosion, unless something was present which inhibited 

 the diastatic action. Nor is it possible that diastase was 

 present only in the pulp cells without starch grains, for it is well 

 known that diastase can diffuse from cell to celU, and the starch- 

 bearing cells were scattered throughout the pulp tissue. 



That there is nothing peculiar in the undissolved stareh 

 grains found in normal apparently healthy apples was found by 

 microchemical examination, with the aid of iodine, potash, heat 

 and polarised light. Nevertheless it was not found possible to 

 dissolve them by the aid of solutions of commercial diastase, 

 freshly-prepared barley diastase or " ptyalin," even after apply- 

 ing fresh diastase solutions daily for a week. Thin slices of the 

 pulp were then washed repeatedly with dilute ammonia, dilute 

 hydrochloric acid and water. The starch grains in the starch 

 cells dissolved partly or entirely after three to seven days in 

 freshly-prepared barley diastase, but even then some cells could 

 still be found with starch grains apparently entirely unaffected. 

 If bacteria or fungi were allowed to develop freely, all the starch 

 grains were dissolved in 3 to 14 days, and by the latter time 

 the pulp cells separate from each other, but may remain with 

 unbroken walls for a. very long time in the absence of cellulos^e 

 bacteria. The starch grains may dissolve before fungal hyphae 

 reach them, and form at first an irregular am.orphous faintly 

 blue-staining mass, or a granular debris in the cells which 

 originally contained clusters of well-defined starch grains. 



Similar results were obtained with natural bitter pit tissue 

 containing abundant starch cells, but here is some cases even 

 after long washing with acid, alkali and water, and in the pre- 



1 When fungi are grown on apples containing starch, the grains may begin to dis- 

 solve while still an appreciable distance from any fungal hyphae, particularly at any 

 point where the growth of the latter is retarded. 



