Bitter Pit in Apples. 381 



two weeks in air distinct pits up to 3 mm. depth had developed 

 beneath all the prepared spots. Similar apples on 100 c.c. of 

 the same water for one week and on water distilled in glass 

 vessels developed no perceptible pits. 



All varieties are not equally sensitive, and Rome Beauties are, 

 for instance, distinctly less sensitive than Jonathans. Thus 

 after similar treatment and times on a solution of 1 gram per 

 million of water, the pits were more superticial and not more 

 than 1 to 2 mm. deep, and no trace of any poisonous action on 

 this variety could be detected with solutions of 1 per 100 mil- 

 lions. There is, however, a possibility that the conditions under 

 which an apple has been grown may affect its resistance to 

 poison, and actual evidence of this is o^iven later, so that ap- 

 parent differences between varieties may not be as prominent in 

 some cases as in others. 



Lead Nitrate. — 



Prepared Rokewoods. — One week in 1 litre of solution, and 

 examined after two weeks in air. 



One per 10,000,000. Pits 1-3 mm. deep beneath each pre- 

 pared spot. 



One per 100,000,000. From no effect to slight superficial 

 browning. 



One per 1,000,000,000. No perceptible signs of poisoning. 



Prepared Jonathans.— One week in 1 litre of solution, and 

 examined two weeks later. 



One per 200,000. Pits from superficial to 5 mm. deep. The 

 Federal Analyst reported, " No lead detected.'' 



One per 1,000,000. Distinct pits up to 2 or 5 mm. deep 

 under some, but not all of prepared spots. The Federal Analyst 

 reported, '' No lead detected.'* 



Lead nitrate is evidently distinctly less poisonous in its action 

 than mercuric chloride, and is slower in its action and penetra- 

 tion than the sulphate of copper. In the following tests with 

 prepared Jonathans, after one week's immersal the apples were 

 kept in air for nine weeks^. 



1 III all cases the apples after washiri}; were kept in the same cleaned gas cylinders in 

 which they had been tested. These keep the apples well aerated and yet in moist air 

 without danger of infection. They keep for a remarkably long time under such circum- 

 stances without shrivelling or rotting. 



