VOL. I.V.3 PHILOSOPHICAL TRANSACTIONS. 20y 



nicate to him whatever had fallen under his own observation, with respect to the 

 disease called Ergot. 



In answer to this letter, Dr. B. was favoured with the following collection of 

 curious facts and observations on the subject of his inquiry: which, at his re- 

 quest, he sent to the r. s. 



After thanking Dr. B. for the present of his treatise de Catarrho et Dysen- 

 teria, Dr. Tissot states that the observations on spurred rye (secale cornutum) 

 inserted in the first edition of his Avis au Peuple sur sa Sante, were not his 

 own, but those of an anonymous Parisian author, and that he had omitted 

 them in the 2d edition of that work ; but in compliance with Dr. B.'s request, 

 he had sent him all the information he had formerly collected on this subject, 

 at a time when his inquiries were particularly directed to Dietetics. The result 

 of these inquiries Dr. B. was at liberty to lay before the r. s. 



Dr. T. then states that there are 3 principal diseases of wheat and rye, viz. 

 the rubigo, ustilago, and secale cornutum. 



The rubigo (mildew in English, rouille in French, ruggine in Italian) is a 

 reddish-yellow, glutinous powder which adheres to the stem and glumes of 

 many graminaceous plants, preventing their growth and depriving the grain of 

 its nourishment, whence it wastes away and becomes shrivelled, and yields little 

 or no farina.* 



The ustilago (nielle or brulure in French, fuligine in Italian) is a generic 

 name, denoting a black degeneration of wheat and other bread-corn, of which 

 there are 2 species, the carbunculus (charbon) and caries (la carie.)-!" 



The charbon is a disease of corn which is scarcely to be distinguished by its 

 outward appearance, except that the grain appears rounder, where the internal 

 substance is converted into a black, viscid, foetid powder. Such grain is some- 

 times much swelled; hence Mons. Duhamel has called this disease la bosse. 

 The nature of the charbon, according to the observations of Mons. Bonnet, is 

 best seen in the grain of Indian corn (maize). (a) He had seen some of these 



* This disease, the mildew, blighf, or rust, according to Sir Jo«. Banks, is occasioned by a minute 

 parasitic fungus which attaches itself to the stems, leaves and glumes. At first it is of an orange co- 

 lour, and afterwards changes to a deep chocolate. See an Account of the Cause of the Disease in Corn 

 called by Farmers the Blight, the Mildew, and the Rust, by Sir Jos- Banks, Bart. p. k.s. illustrated by 

 engravings, showing the biightasitappearswhen viewed throughglassesof very high magnifying powers. 



+ The carbunculus or charbon corresponds with what is called by the English farmers rotten wheat; 

 the caries, as here described, with the smut, which others term ustilago. 



(a) Recherches sur I'Usages des Feuilles dans les Plantes, p- 327- Dr. Tissot's description is not 

 sufficiently explicit. Mons. Bonnet's words are " lis (les grains) ctoient composes interieurement 

 de plusieurs feuillets poses les uns sur les autres, et qui laissoient entreux des vuides. Ces vuides 

 ctoient remplis par une poussiere noiratre, &c." 



VOL. XII. E B 



