Apr. 14. *^*3 Internal Browning of the Yellow Newtown Apple 
175 
a decrease in the permeability which is reversible and the subsequent 
increase in permeability is due to the accumulation of toxic substances as 
a result of the action of the anaesthetics. In 1910 Armstrong {2) and 
his co-workers showed that, imder the influence of anaesthetics and certain 
other substances which they called hormones, reactions occur in tlie cells 
which indicate that the enzyms and their substrates were brought into 
contact. Among the results of this mixing of the enzyms and substrates, 
as observed by these workers, was an oxidation which resulted in pig¬ 
mentation. These workers also state that these phenomena are cons¬ 
tantly taking place in the plant but that under normal conditions their 
products are passed off before they become injurious. Under abnormal 
conditions, however, they may accumulate in sufficient amount to 
greatly hinder the activities of the tissues and eventually to cause the 
death of the cells. Giglioli (9) found that essential oils markedly influence 
the movements of water, enzyms, and soluble substance tlmough the 
cell membrane. Later, Giglioli (jo) also demonstrated that the enz)nns 
could be removed from yeast cells by rendering them permeable with 
essential oils. 
During the past year Power and Chestnut (14) have isolated the 
essential oils of the apple. They have shown conclusively that essential 
oils are being produced continuously by the apple in sufficient quantities 
to be detected* In 1919 Brooks, Cooley, and Fisher (5, d, 7) found that 
apple-scald, a nonparasitic storage disease which is generally confined 
to the surface of the fruit, was apparently due to volatile substances 
which are produced by the fruit when held for some time under the more 
or less abnormal conditions of storage. In substantiating this contention, 
they present data which show that the disease is reduced to a minimum 
by removing these volatile substances from the fruit by air circulation 
or by storing the fruit in wax or oil wrappers that are known to be good 
absorbents of essential oils. 
After making observations upon the appearance of the fruit in internal 
browning and in advanced stages of apple-scald, the writer became 
convinced from the firmness of the tissue and the way in which these 
diseases spread into the flesh of the fruit that there is a similarity between 
these two storage diseases. Histological examinations of affected 
tissues further emphasized the analogy which exists between these diseases. 
For the histological studies, sections of the apple torus were cut by means 
of a freezing microtome. The sections were dropped directly from the 
razor into acidified absolute alcohol which fixed them and prevented any 
additional browning. They were then passed through xylol and mounted 
in Canada balsam without staining. The examination of a large number 
of cells brought out a very striking similarity between browning and scald 
in the progress of the discoloration in the tissues as well as in the individual 
cell. In 5 ie tissue there was no regularity in the spread of the disease from 
one cell to the other, since isolated cells showing browning were always 
found to be scattered among the normal cells near the regions of scald 
or browning. In the cells in which the progress of the browning could 
be followed it was found to be identical in the two diseases. The brown¬ 
ing started at the periphery of the cell and from there spread to all parts 
of the cell along ^e more concentrated strands or areas of cytoplasm. 
Hie discoloration was, as a rule, more intense in the region of the nucleus 
which is near the surface in the apple cells. Plasmolysis accompanies 
the advanced stages in browning, until, in the very severe stages, the 
