The Cause of Bitter Pit. ] 7 



observations seem to indicate that biie complaint known as bitter pit 

 is, strictly speaking, not a disease at all, but rather a symptom 

 of slow local poisoning, and that in the cases actually examined so 

 far it appears to be due to the poisonous compounds sprayed on to 

 the surface of the fruits." 



" Though as far as my observation and experiments go, I have 

 limited them to the supposition that the spray passes through the 

 breathing pores of the fruit, from the exterior, it is by no means 

 impossible that some of the spray which falls on the ground or is 

 washed down by the rain, and gradually accumulates in the soil, 

 might enter the plant through the root hairs. That soil is capable 

 of retaining arsenical compounds for a considerable length of time 

 is well known, and when an orchard is sprayed 6 to 16 times in one 

 season2 the amount of jjoisonous spray reaching the soil must 

 become quite appreciable. The sensitive fruit cells would probably 

 be more susceptible to poison than the other parts of the plant, 

 since the living protoplasm is reduced to a mere attenuated film, 

 but this would necessarily be a matter for future investigation." 



The statement that Dr. White's original theory has been aban- 

 doned and another substituted for it is therefore highly misleading. 

 The essential point is that the complaint known as bitter pit is not 

 a disease but a symptom of slow local poisoning, and evidence in 

 support of this is steadily accumulating. The nature and origin of 

 the poisons in question is a subsidiaiy matter. Dr. White informs 

 me that as the result of several years' work on testing the influence 

 of poisons on Prickly Cactus and other plants, she has come to the 

 conclusion that bitter bit symptoms are not confined to such fruits 

 as the apple and pear, but may also occur in leaves and stems, and 

 as in the apple and pear may not only occur naturally but may 

 be produced artificially by the direct application of poisons. It is 

 indeed possible that certain obscure plant tumours and malforma- 

 tions may be the direct or indirect result of oligodynamic poison- 

 ing. 



Potatoes grown in newly cleared acid soils often develop brown 

 spongy patches of dead tissue internally which are not accom- 

 panied by any disease organisms. This and the disease known as 

 " brown fleck " may be further instances of natural oligodynamic 

 poisoning. The dead cells here also contain undissolved starch 

 grains in quantity, whereas in dead patches produced by parasitic 



2 Largely as the result of Dr. White's work sprayinsr is no lonarer carried to the absurd 

 extremtsfc hat were formerly common, and it is more generally recognised that the smaller the 

 amount of poisonous material used to produce the result required, the better it is for the plant and 

 for the soil. 



