348 Alfred J. Ewart : 



Mercuric chloride. 



(3) 1 gram per 10,000 c.c. All the spots with brown pits 2-4: mm. 

 deep. 



(4) 1 gram per 100,000. All the spots witli brown pits 1-3 mm. 

 deep. 



(5) 1 gram per 1,000,000. All the spots with brown pits 1-2 mm. 

 deep. 



(6) 1 gram per 100.000 in 3 % sodium chloride. 



(a) Browned and invaded by Pcnicillium. 



(b) Yates. Rather pale pits to all the prepared spots 



1-2 mm. deep. 



(7) 1 gram per 10,000 in 3 % sodium chloride. Large deep pits 

 to all the prepared spots 4-6 mm. deep.^ 



(8) In 3 % sodium chloride alone. 



(a) From superficial browning to pits i mm. deep. 



(b) Yates. Superficial browning. No distinct pits. 



Copper Sulphate. 



(9) 1 per 10,000 in 3 % sodium chloride. 



(a) Large well-defined pits 2-3 mm. deep, but paler than 



with copper sulphate alone. 



(b) Yates. Large pits, but ap])le invaded by Penicillium 



through a bruise. 

 (10) 1 per 100,000 in 3 % sodium chloride. 



(a) All the piepared spots b)owiied, pits pale, barely ex- 



ceeding I mm. deep. 



(b) Yates. As above, but. pits not exceeding 1 mm. 

 (11) 1 per 100,000 (co])pei' sulphate alone). 



Large dark pits to all tlie prepared spots 3-4 mm. deep. 



These results closely coincide with those already published by me, 

 and show that dilute metallic jjoisons produce browning and pit 

 formation in the presence of isosmotic solutions of sodium chloride, 

 the entry here taking place by diffusion only. Further, Graven- 

 stein apples appear to resemble Five Crowns in their greater sen- 

 sitivity as compared with Yates. In a pale-skinned apple it is 

 difficult to be sure that the I'ut has not gone too deep, whereas in a 

 red apple the fragments removed from the skin must show no colour. 

 If they do, the cut has passed through the hypodermal layers. 

 Further, in soft-fleshed apples some of the prepared spots may be 



1 The mercuric chloride kills the cells before sufficient s-ilt has entered to prevent browninif. 



