136 ON GEAPE MILDEW, 



time which has elapsed since they were infested, the greater or 

 less vigour of the fungus, «fec. When the fruit is sharply 

 attacked, and at a time when it has arrived at about half its 

 growth, or when it is scarcely so large, since the outer diseased 

 skin cannot keep up with the expansion of the juicy parenchym, 

 it splits longitudinally into many lobes, so that the seeds, wiiich 

 are more or less perfectly developed, are exposed, as in the rup- 

 tured capsvde of an Euonymus. These fissured berries seem, 

 under all circumstances, incapable of further development ; they 

 remain small, although they hang on the vine till late in the 

 autumn, and seem at last to dry up or rot ; at least I saw in 

 none any symptoms of becoming ripe. On tlie contrary, if the 

 fruit is attacked towards autumn, when it is already much 

 advanced in its development, the influence of the fungus is too 

 weak to prevent the production of ripe, perfect, normal fruit, 

 even when the stalks of the berries are thickly overrun with its 

 tlireads. Between these two extreme cases a number of inter- 

 mediate conditions naturally occur, in which the berries do not 

 crack, but are arrested in their growth, and never ripen or become 

 profitable. 



The question whether the use of diseased grapes has any 

 noxious consequences, seems not to be decided. While, on the 

 one side, a string of examples from French papers is brought 

 forward in the Reforme Agricole, according to wliich diseased 

 grapes are injurious, producing colic and vomiting, express 

 experiments to a contrary eflfect have been communicated to me 

 in Lausanne. Probability is in favour of the latter opinion, 

 since the extent to which the malady has lately reached in 

 France could not fail to have aflTorded a number of well-esta- 

 blished examples, if the diseased grapes were really injurious, for 

 they were frequently eaten by children. 



It is a natural question, what will be the condition of the dis- 

 ease in future ; is it transitory, brought on and favoured only by 

 accidental and temporary circumstances, or is it a durable evil, 

 and what remedy, in this case, can be administered for the 

 warding off or diminution of the malady? We are treading 

 here on dangerous ground, for it is notorious how little, for the 

 most part, in epidemic diseases, science is in a condition to answer 

 such questions, and the potato murrain affords a lamentable 

 instance amongst vegetable epidemics how little the numerous 

 solutions of the difficulty, and these frequently given with no 

 less confidence than imperfect knowledge, serve for the removal 

 of the evil. 



The question as to the future condition of the malady, whether 

 it will vanish or extend step by step to the districts which at 

 present are uninfected, is, from the very nature of the case, per- 



