22 



BITTER PIT INVESTIGATION. 



When a thin section of such a bruised portion is made, the cells of the flesh are seen to be broken 

 and collapsed, and of a yellowish-brown tint, but it is very noticeable that the adjoining fibro- 

 vascular bundles are not generally discoloured as in Bitter Pit. In connexion with the discoloured 

 cells, there are also tufts of filamentous colourless cell-rows, sometimes branched and usually 

 projecting into the cavities produced. The browning likewise extends inwards from the epidermis, 

 and this is another point of distinction from Bitter Pit, when there is an artificial bruising from the 

 outside. 



The Yates variety was chosen for these observations because it is not subject to Bitter Pit. 



EFFECTS PRODUCED BY CHEMICAL RE-AGENTS. 



It is stated by Wortmann (97) that if apples are punctured with a needle and placed in 

 solutions of an alkaline or acid character, pitting is produced which cannot be distinguished from 

 the natural product. There is only a superficial resemblance, and, although experiments were 

 carried out with various reagents, such as lime water, potassium tartrate, chloroform, oxalic acid, 

 &c, I will only give the results obtained in three cases, viz., citric acid, malic acid, and corrosive 

 sublimate or mercuric chloride. 



Citric Acid. — A 10 per cent, solution was used, and Jonathan apples, both punctured and 

 unpunctured, were immersed in it on 6th July, and finally removed on 28th August, so that they 

 were immersed for a period of 53 days. This solution produced a visible effect upon the skin 

 (Fig. 57). The unpricked apple showed depressed spots most numerous about the equator, often 

 round and sometimes confluent. These spots were not unlike those of Bitter Pit externally. In 

 order to see if there was any deeper resemblance, a section was made, but this only showed the 

 normal tissue beneath the skin, and there were no starch-grains visible in the cells of the flesh, even 

 after treatment with iodine solution. 



The pricked apple showed the punctures just as if freshly made (Fig. 57a), and on making a 

 section the cavity was seen to be quite distinct, without any change in the flesh adjoining. The 

 depressed spots were distinct from the punctures, and confined to the skin. Both apples had 

 changed in colour to a reddish-yellow. 



There was thus no production of Bitter Pit by means of this or the other reagents tried, and, 

 even where the skin was affected, as in the case of citric acid, it was only superficial. 



Malic Add. — Pure crystals were used, and a 10 per cent, solution made. Mature Yates 

 apples were kept in this solution for 24 hours, both pricked and unpricked, the puncturing being 

 done with a sterilized needle. 



In the unpricked apples there were round discoloured spots, very slightly depressed, about 

 3-4 mm. in diameter, and, when cut through, the tissue for a short distance beneath the skin was 

 pale-pinkish and assumed a crescent shape corresponding to the external spot. 



In the pricked apples there were isolated spots discoloured and slightly depressed. Where 

 there were four punctures together, in the form of a cross, the external discolouration took the same 

 form, and sometimes extended to \\ inches. There was a pinkish colour given to the tissue beneath, 

 extending as deep as the punctures. 



Corrosive Sublimate. — Various poisons were employed which were highly soluble and 

 extremely penetrating, so that the effects were produced very rapidly, and corrosive sublimate or 

 mercuric chloride may be taken as an illustration. A saturated solution in alcohol was employed, 

 and a small portion of the surface was rubbed over with sterilized cotton-wool steeped in the 

 solution. Mature apples of the Yates variety were used, and results were taken at the end of 

 48 hours. It produced a discolouration to a yellowish-brown tint, which extended a little beyond 

 the area where it was applied, with a very distinct raised edge (Fig. 58). The discoloured portion 

 was perfectly smooth and bright, and there were no pits or depressions of any kind. When a section 



