Bilter Pit (lad Sensifl rili/ to Poisons. 233 



by this treatment was overlooked. The bitter pit ash ol)tained by 

 incineration contained over 70 per cent, ot" added sand, and the 

 possibility of a formation of insoluble silicates (lead silicate, etc.) 

 needs consideration. Finally, 10 per cent, nitric acid is not a 

 general solvent for metals or metallic oxides, and in insoluble 

 form a poisonous metal is comparatively harmless. 



In other experiments the pitted tissue was directly tested by 

 leaving it in contact with diastase solutions for a day. then 

 filtering off and testiu<j: the diastase with starch solution. The 

 authors state that the action of malt diastase was strongly acceler- 

 ated after contact with boiled and unboiled bitter pit pulp, and 

 normal pulp, and that with taka diastase, practically no effect 

 was exercised. On repeating these experiments with filtered solu- 

 tions of malt diastase dissolved in distilled water, I am able to 

 give them emphatic contradiction. Prolonged contact with pounded 

 apple pulp, boiled^ or unboiled, bitter pit or normal, practically 

 destroys diastase in 1 to 3 days2. and unboiled pulp, if anything, 

 appeal's to be more active than boiled. 



Even contact for a sliort time with pounded apple pulp retards 

 or inhibits diastatic action. Thus (A) 20 grams of pounded 

 apple pulp, and (B) 20 grams previously heated to 100^ C. for 

 15 minutes, were added to separate 10 c.c. of 1 per cent. Taka 

 diastase, and at once filtered. In three hours 5 c.c. of each filtrate 

 were added to 10 c.c. of 0.5 per cent, starch, and a control con- 

 tained 10 c.c. of 0.5 per cent, starch to 5 c.c. of 0.33 per cent. 

 Taka diastase. 



The solutions were kept at 35° C, and portions tested at inter- 

 vals with iodine. In (A) the liquid was brow-n, and develoj^ed a 

 large, brown coagulum, which was shaken up before testing. In 

 (B) the liquid was colourless, and formed a smaller precipitate, 

 later nearly all dissolving. 



3 Hours. 6 Hours. 16 Honr.s. 3u Hours. 



(A) - Blue. - Bhie. - Bhie. - Blue. 



(B) - Blue. - I'urplisli hlue. - Purple. - Purjjle. 

 Control - Palei- ]>\w. - Purple. - Nil. - Nil. 



On testing (A) and (B) the former contained distinctly more 

 tannic acid. Apparently in the heated pulp a good deal of the 

 tannic acid combines with the coagulated proteids of the cell. 



1. Out of contact with water. 



'J With prolonged exposure a portion of the action appears to be due to the diastase destroj'ingr 

 itself when in solution even at low temperatures such as 14 or 15°C. (See Czapek, Biochemie, vol 

 i.,p. 345.) 



