Fig. 3. Apple attacked by 

 ripe rot. A section has 

 been removed so as to show 

 how the rot penetrates. 

 The concentric arrangement 

 of the pustules is shown. 



Concentric Arrangement of the Pustules. (See Fig. 3.) 



I am not aware that the concentric arrangement of the pustules of 

 the Gloeosporium has received an explanation. I formerly ventured 

 to propound the query whether this arrangement was not the result 

 of diurnal variations in the growth. Observation in connection with 

 the following series of inoculations has con- 

 vinced me that there is nothing in that idea. 

 I am more inclined to think that the concentric 

 arrangement is due to successive waves of 

 growth. In the formation of this theory the 

 chief idea is that when a series of pustules 

 has become ripe, i.e., arrived at the spore- 

 producing stage, perhaps some of the spores 

 germinate, or some of the peripheral mycelia 

 rejuvenate, and having perforce to grow out- 

 wards in search of food, create as it were a 

 new spore bed, which in turn gives rise to a 

 new set of pustules, and so on indefinitely. 

 Under this theory each ring of pustules rep- 

 resents a new " generation" of spores, or a 

 fresh wave of growth, and there will be as many rings of pustules as 

 there are " generations" or waves. This theory seems to accord closely 

 with the known facts. 



Whenever in the course of these observations terms such as Guava 

 Gloeosporium and Banana Gloeosporium are used, nothing more is 

 meant than that the form mentioned was found growing naturally on 

 the guava or on the banana as the case might be. It should not be 

 inferred that the terms mean more than this unless there is a 

 definite statement to that effect. Thus when the term Banana 

 Gloeosporium is used it must not be thought 

 this term is synonymous with Gloeosporium 

 musarum. It may be or it may not. Some 

 basic principle had to be adopted, and it 

 seemed best to use the occurrence in nature 

 as the foundation of the system of reference. 

 At an early stage of the inoculations it seemed 

 certain that the hitherto accepted nomenclature 

 was inadequate, and I was forced to fall back 

 upon the above plan as the next best thing. 



It was most interesting to watch the pro- 

 gress of the diseased spot that arose from an 

 inoculation. According to the fruit experi- 

 mented with, according even to the variety used, so would there arise 

 certain peculiarities in the growth of the fungus. The growth on the 

 pear was somewhat different from that on the apple, and on the latter 

 again differed from that on the quince. The different varieties of 

 apple presented their peculiarities in the inception and progress of the 

 disease ; nay, even the stage of ripeness at the time of inoculation 

 exerted a marked influence. 



Fig. 4. Ripe-rot pustule 

 from an Apple, magnified. 



