INTRODUCTION TO CKYPTOGAMIC BOTANy. 309 



takes i^lace while the fruit is still hanging on the branch. It 

 is curious that, as these moulds affect the living tissues of plants, 

 a species not distantly allied should be no less destructive to 

 silkworms, more especially in the larva state, though the pupa 

 is sometimes affected in the cocoons. Where the disease has 

 once made its appearance, nothing will arrest it except the most 

 complete sanatory measures ; every jDart must be well washed 

 with chloride of lime or some other disinfecting substance, 

 which can act effectually on the spores, and a new stock must 

 be procured from an uninfected place. Careful ventilation 

 and extreme cleanliness are undoubtedly great points as regards 

 the prevention of the disease. It has not yet been ascertained 

 whether the Fungus which attacks flies belongs to the same 

 genus. It is probable, however, that what is called S'porendo- 

 nema Muscce, is merely an incipient state of some more highly 

 organised Fungus. 



o29. The subject of fermentation has already been men- 

 tioned. J must, however, add a few words. Though mycelium 

 is produced in fermenting liquors under particular circum- 

 stances, the appearance called ropiness in wine is not due to 

 such a production. It arises from a peculiar state of fermenta- 

 tion, in which lactic acid and mannite are formed, together 

 with a mucilage from which the ropy appearance in question 

 arises.* The forms assumed by the secondary fruit of Asper- 

 gillus glaucus, Dactyliuon roseuni, and the parasitic species 

 of Botrytis, have already been noticed. -|- Pafuloispova (Fig. 

 Q^, 6), one of the most beautiful of moulds, produces heads 

 of a cellular structure, from the centre of each mesh of which 

 an oblong spore is developed, which was not observed by 

 Preuss, the founder of the genus. The same thing occurs in 



* It sometimes liappens in France, that dough is so constantly ropy 

 in certain bakehouses, that they become worse than useless. As in the 

 case of Silkworms, just mentioned, the only remedy is to cleanse the 

 walls thoroughly, and wash them with some substance destructive to 

 Fungi. 



t It may be added that Caspary finds in Bot. UmhelUfemrum, instead 

 of the large solitary encysted spore, vesicles filled with minute sporidia 

 {Sporidangia). 



