DISEASE OF THE VINE. 233 



(a question nevertheless deserving further investigation with the 

 assistance of data, which are not vrithin my reach from those 

 distant countries), I think I may affirm that the cryptogamous 

 plant which prevails (for many others accompany it) on our 

 diseased Grapes in Tuscany is not the Erysiphe communis as the 

 Sig. Berenger asserts. To he convinced of it, it suffices to cast 

 your eye on this voluminous green Grape as modelled in wax and 

 magnified to one hundred diameters, from the surface of which 

 arises a network of white filamentous mycelium, somewhat branched, 

 and interwoven in various ways, or here and there intersecting 

 itself, without any apparent regularity. From these filaments, 

 which consist of tubes of extreme tenuity closed at various intervals 

 by transverse partitions, arise, almost at right angles, others of a 

 club shape, from the enlarged summits of which proceed amoniliform 

 series of utricles which readily disarticulate, separate from each 

 other, and are scattered in various directions. These constitute 

 the vegetating frond, or the sterile plant seen by all owners of a 

 microscope, in which an eminent botanist has thought he found 

 characters sufficient to distinguish the fungus as a species. But 

 no one appeal's as yet to have succeeded in prosecuting researches 

 to the point of ascertaining the real fructification of the cryptogam. 

 This fructification arises from the apex of the ascending filaments. 

 It is first indicated by a rather transparent cell of pale yellow, 

 which, as it increases in size, passes to an orange yellow, and at 

 its maturity acquires a much darker hue. These cells vary in size 

 as well as in form ; some are spherical, others of an oval shape 

 more or less elongated, some of the size of the white utricles of 

 the frond, but in general they are larger, surpassing them some- 

 times by one-third of their length and breadth. 



It was in October, 1851, that I first found a fructification 

 nearly similar to the one in question, on an analogous cryptogam 

 on the gourd, but, as I had then no means of demonstrating its 

 origin, I did not venture to publish it, as there remained doubts 

 in my mind whether the organs I then found intermingled might 

 not belong to two different plants. But ulterior observations have 

 caused these doubts to disappear entirely, for, adopting the use of 

 reflected light in order to observe the objects without altering 

 their natural position, I could see the stalks of the sporangia 

 inserted into the same filaments of the mycelium from which 

 proceeded the sterile fronds. Besides that, I often met with 

 fructifications having one of the white utricles directly attached 

 to their free extremity, so that the evidence of the passage or 



