380 Alfred J. Ewart: 



One per 25,000,000. Pits from 2 to 6 mm. diameter, and 2 

 to 4 mm. deep beneath each prepared spot. 



Immersed one week and examined after two weeks in air. 



One per 50,000,000. Distinct brown pits from 1-3 mm. deep 

 beneath each ])repared spot. 



One per 100,000,000. Same as preceding, but pits a little 

 fainter and shallower, and some spots showing a little super- 

 ficial browning only. 



One per 1,000,000,000. Three pits 2 mm. deep, two of pre- 

 pared spots with a brown rim, rest no signs of poisoning. 



One per 10,000,000,000. One prepared spot with faint brown 

 rim, rest unaffected. 



One per 100,000,000,000. No trace of any poisonous action. 



In pure copper-free, distilled water, no diseased tissue at the 

 prepared spots, pits or marks of any kind. 



Copjje?' S u Iph ate. — 



Prepared Jonathans. — One week in solution, and examined 

 after a week in air. 



One gram in 100,000 c c. (250 cc. of solution). Well developed 

 pits up to I cm. diameter, and mostly 2-3 mm. deep. 



One per 200,000. Pits well developed. The Federal Analyst 

 reported, " No copper delected." 



One per 500,000. Pits well developed, some nearly 5 mm. 

 deep. 



One per 1,000,000. Pits less developed, but some 3 to 5 mm. 

 deep. The Federal Analyst reported, " No copper detected." 



One per 2,500,000. Pits beneath each prepared spot, but none 

 exceeding 2-3 mm. deep. 



One per 25,000,000. Superficial browning to pits with dead 

 tissue, not exceeding 1 mm. beneath most of the prepared spots. 



One per 100,000,000. Slight superficial browning at some of 

 the prepared spots. 



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



Hence, although the pulp cells of apples are extraordinarily 

 sensitive to copper sulphate, they are less so than to mercuric 

 chloride. Nevertheless the traces of copper sometimes present 

 in distilled water are sufficient to affect them. Thus a prepared 

 apple was floated on 250 cc. of water distilled in a copper vessel 

 and tubes. The water was renewed daily for one week, and after 



