138 



smut vesicles in the diseased cells, and then these vesicles 

 are found in great masses lying close together, filling entirely 

 the diseased organ and frequently without leaving a trace of 

 the original intervening cellular wall. 



M. Leveille* read a paper before the Philomathic Society 

 of Paris on the Uredines, in which he contests both M. Tur- 

 pin's view and that of M. Unger on the origin and significa- 

 tion of these formations. He considers the Uredines to be 

 true parasitical fungi and not diseases of the plants on which 

 they occur ; they are said to originate from a byssoid tissue 

 beneath the epidermis of the plants. Probably M. Leveille' 

 will publish more detailed communications on this subject to 

 prove his statements, with which, as far as they have been 

 made known, I cannot agree ; but his observations also prove 

 that the view advanced by M. Unger, that these plants should 

 be regarded as diseases of the respiratory organs, is not cor- 

 rect, for they all take their origin in the cells. 



M. von Voithf has described certain abnormal formations 

 which he observed on the wood of the elm ( Ulmus) : they are 

 triangular bodies which proceed from the bark into the interior 

 of the wood. Since the microscope was not at all employed 

 in examining these formations, and I cannot find them in the 

 wood of the elms occurring in the neighbourhood of Berlin, 

 it is impossible for me to come at any correct notion of them 

 from the description, for it is not even stated whether the foreign 

 body consists of bark substance or of wood. I am rather in- 

 clined to suspect that these diseased formations are derived 

 from bark substance and that the cause of this deformity must 

 be sought, as M. v. Voith suspects, in the ascending of the 

 trees with iron points, by which the bark has been squeezed 

 into the wood, but not destroyed. The new annual rings of 

 the wood forced their way afterwards through the apex of the 

 impressed bark, &c. If my suppositions are correct then all 

 the rest is easily intelligible. 



M. Dutrochetfs communication on the formation of the 

 ergot was noticed at p. 117. 



Numerous experiments have again been performed on the 



* L'Institutde 1837, p. 191. 



f Ueber em sonderbares Gebilde in der Ulme. Flora von 1837. No. 17. 



