EXUDATIONS AND ROTTING. 231 



In advanced stages there is much gummy 

 material in the lumina, and even large cavities 

 filled with this gum may be found. 



The rot of Cherries, Pears, Apples, Plums, etc., 

 in store may be due to several fungi, of which 

 Botrytis, Monilia^ Mucor, Penicilliuin^ and Asper- 

 gillus are the chief The fruit may be attacked 

 while still on the tree, but very often fungi and 

 bacteria gain access to the tissues, through bruises, 

 cracks, etc., formed in the fruit lying in the storage 

 baskets or on the shelves. 



Rot in Onions, Hyacinth bulbs, etc., is frequently 

 due to the access of Botrytis or Sclerotinia, 

 followed by moulds, yeasts, and bacteria in the 

 stores. 



Sour-rot in Grapes, and other fleshy fruits 

 which need much sun to ripen them, is probably 

 a usual result of continued cold, wet weather at 

 the cropping season, setting in when the fruits 

 are beginning to swell. 



Flux. It is a common event to see fluids of 

 various kinds issuing from wounds in trees, or 

 congealing in more or less solid masses about 

 them ; and owing to the prevailing tendency to 

 compare plant diseases with those of animals, we 

 find such expressions as Gatigrene, Ulcer, and so 

 forth, applied to these " open sores." In so far as 

 such outflowings frequently indicate diseased states 

 of injured tissues which are incapable of healing 

 up, the analogy is perhaps a true one ; but it 

 must be remembered that very different structures 

 and processes in detail are concerned. Moreover, 



