300 Pflanzenkrankheiten, 



their researches about the Jonathan spot rot, in which they do not 

 believe that there is sufficient data for affirmation of either of the 

 two tentative theories as to the cause of this disease. Though it is 

 not possible to announce any definite conclusions, a few Statements 

 can be made; 



1. The nuniber of Spots on apples ba2:ged previous to June 9 

 was much less than on those bagged after that date. 



2. The relative injuries due to Spotting is expressed in an in- 

 complete table, in which we find, that on Nov. 13, 1913 from bagged 

 apples 72% was without spots, on Nov. 28, 1913 from unbagged 

 apples 21% unspotted, and on Jan. 8, 1914 (part of same fruit as 

 inspected Nov. 13, 1913) 427o unspotted. It will be noted that the 

 bagged apples were in far better condition than those that were not 

 bagged. This may be considered a fair representation of the resuits 

 obtained. If the spot is physiological, it appears that we might 

 reasonably expect approximately as much Spotting on the fruit in 

 the bags as on that not in bags. On the other hand, the fact that 

 fruit or twigs were not disinfected before bagging makes it possible 

 that spores were imprisoned in the bags and were the cause of the 

 Spotting. 



3. The smaller, nearly black, typical "Jonathan" spots are more 

 commonl}^ confined to the dark area of the skin. 



4. The rather large, light-brown ''Alternaria" spots are more 

 common on the lighter area of the skin. 



5. There are spots occurring on an}^ area which are hard to 

 classify as one or the other of the above and which grade into one 

 or the other, These are not so common as the clearly distinguish- 

 able Spots. 



6. Many of the "Jonathan" spots are surrounded by a light- 

 brown area characteristic of the "Alternaria" spots. 



M. J, Sirks (Haarlem), 



Keefer, W. E.« Pathologie al histology of the EiidotJna 

 canker of chestnut. (Phytopathology. IV. p. 191—200. 1914.) 



The investigations recorded in this paper were underlaken 

 with a view to determining the nature of the changes produced in 

 bark and sapwood of Castanea dentata when invaded b}^ Endothia 

 parasitica, by a comparative study of the anatomy and histology 

 of normal and diseased tissues from stems of one year's growth 

 and sections of the bark and sapwood from trees quite mature. A 

 brief description of the structure of the normal tissues is first given 

 and then the changes that have taken place due to the invasion 

 of fhe fungus. 



Under the heading "The prim.ary cortex" all the tissue from 

 the cork tissue on the extreme outside of the stem to the inner- 

 most, internal cork layer of the pericycle is included (cork tissue, 

 collench3^ma, thin-walled parenchyma, sclerench3^ma). 



The term "pericycle" is applied to the tissues which lie between 

 the primary cortex and the bast zone. This includes the successively- 

 formed internal cork layers, the sclerenchyma which is made up 

 of bast fibers and stone cells, parenchyma and the crystal-contai- 

 ning cells. 



The bast zone lies directh^ between the pericycle and the cam- 

 bium layer and is chiefly composed of sclerencln'ma in the form 

 of bast fibers, although this portion of the stem also contains sieve 



