Bitter Pit in A^ijples. 373 



paraffin, and the time of immersal shortened to three and a-half 

 days. The whole surface was affected, and more or less pitted 

 and wrinkled. In one week the whole superficial pulp was 

 browned in spots to a depth of 1 to over 10 cms. The Federal 

 Analyst reported tha.t " the quantity of mercury compounds re- 

 covered from the peel of the twelve apples was 0.036 gramme 

 (as metallic mercury) and from the brown-coloured spots of the 

 pulp 0.009 gramme. The amount of mercury recovered is con- 

 sidered to be less than that actually present." This is because 

 of the relatively large bulk of organic material, which might 

 in extreme cases cause reductions in the apparent amounts 

 present, up to as much as 20 or even 25 per cent. Even then 

 the total amount of mercuric chloride entering the apples would 

 not exceed 0.06 gram, and that in the pulp 0.012 gram. This 

 was spread over not more than one-third of the 1890 c.c. bulk 

 of apples. Hence the concentration in the dead pulp after 

 three and a-half days could not have been more than 1 in 5000, 

 or l-25th of that in the liquid outside. 



A third experiment similar to the preceding one was per- 

 formed with four wiped Jonathans, immersing them for three 

 days in a 1 per 1000 solution of mercuric chloride. After well 

 washing and keeping in air for 14 days, the whole surface was 

 brown, discoloured and irregularly pitted, with brown pulp from 

 2 to 20 millimetres deep in parts. From these apples the Fede- 

 ral Analyst recovered 0.004 gramme as metallic mercury from 

 the peel and pulp together. The apples had an original volume 

 of 615 cc. The two litres of solution used contained 2000 milli- 

 grams, of which only four were absorbed by the apples. Here, 

 as in the previous experiment, the concentration within the 

 apple was very considerably less than that outside, and the 

 concentration of poison in the deeper layers of dead pulp must 

 have been oxtremly small. 



Additional evidence of the influence of a waxy bloom in pre- 

 venting the entry of poison was obtained by painting apples 

 over rapidly with a very thin coat of low melting point paraffin. 

 At a casual glance these apples showed nothing abnormal in 

 appearance. Close examination was necessary to detect the 

 treatment they had undergone. They were floated on half per 

 cent, solutions of mercuric chloride, copper sulphate and lead 



