APPEARANCES MISTAKEN FOR BITTER PIT. 



21 



round, and in some instances the skin was cracked in the cavity. The skin had the appearance of 

 being pushed in, and not of being shrunken as in Bitter Pit. When a transverse section was 

 made through the depression, the tissue was seen to be browned beneath in the shape of a crescent. 

 Under the microscope, the section showed the epidermis to be either entire or broken, but the 

 hypodermal layer of cells was flattened and squashed. The browned cells of the flesh immediately 

 b3neath that were generally of their natural size and shapa, and not collapsed as in the case of 

 Bitter Pit. 



On examining other varieties of apple, similar depressions were found, even on Yates, which 

 is not liable to Bitter Pit, so that the evidence was all in favour of the hail having caused the 

 markings. Besides, the depressions were clearly caused by a pushing in of the skin, and not a 

 shrinking of it, as is so noticeable in Bitter Pit. 



It does not necessarily follow that all the markings were freshly caused on the previous 

 day, for on the 28th September, when the fruit had already set, there was also a hailstorm, which, 

 although not noticed at the time, would affect the young and tender fruit. When the skin is 

 unbroken the fruit will not show any evidence of the depressions later on, but if broken there will 

 always be a mark left. 



Hail-marks are generally indicated by being on one side of the fruit, by the skin being broken 

 at least in some spots, and there are often elongated markings without any break, showing where 

 the hail glanced off the skin. 



BEUISED SKIN. 



When a healthy apple is bruised without breaking the skin, such as making a slight depression 

 in it, the pressure causes the cells beneath the skin to turn brown afterwards, and, on examining 

 the brown tissue, the symptoms are found to be similar to those of Bitter Pit. 



Lafar (47), in the English translation of his Technical Mycology in 1898, attributes the 

 " brown spotting " of the apple, that is, the spotting of sound apples under the rind, to some 

 mechanical action. Whenever the cells become ruptured, from the dropping of the apple from the 

 tree or pressure in packing or transit for example, then the oxygen is afforded an opportunity to 

 act on the exposed constituents of the plasma. The enzyme found in the apple by Lindet (107) in 

 1893 carries the oxygen to the tannin, and the result is that dark-coloured oxy-compounds are 

 produced which are precipitated on the cell-walls as a permanent dye. This view explains the 

 discolouration of the tissue, but does not account for the development of the brown spotting while 

 the apple is still growing and attached to the tree, where external mechanical agencies are excluded 

 from the very nature of the case. 



Then, Stewart (88) in 1899 also observed the effect of the bruising, and found the bruised 

 tissue loaded with starch, while the adjoining uninjured tissue was free from it. If the bruises were 

 made before the ripening of the fruit, then the starch would not undergo any further change, since 

 on the death of the cells their activities ceased and the transformation of starch into sugar was 

 arrested. As the fruit ripened, the starch would disappear in the healthy cells, and hence the contrast 

 between the contents of the injured and uninjured tissue. Varcollier (119) in 1904 observed that, 

 while ripe apples contain little if any starch, bruised apples contained large amounts in the vicinity 

 of the bruise. He investigated the cause of this, and came to the conclusion that the action of the 

 tannin on the diastase prevents it from transforming the starch into soluble sugar. But the death 

 of the cslls, in my opinion, is quite sufficient to account for the persistence of the starch in the 

 bruised cells. 



Although an external bruise produces symptoms resembling those of Bitter Pit, yet, since 

 the latter originates from within without any external pressure, there are various differences. 

 When a green apple is artificially indented in the skin, without breaking it, a browning of the tissue 

 beneath soon appears, and after repeated trials it was found to occur usually in twenty minutes. 



