ON THE PROPAGATION OF BUNT. 



109 



ascertain, if possible, the conditions under which such parasites 

 are developed. Probably from the lateness of the season, when 

 my attention was more particularly called to the subject by a 

 communication from the Irish Commissioners, I did not succeed 

 in 1845 in making the spores germinate, though M. Decaisne 

 informs me that he found no difficulty in doing so. They ger- 

 minated, however, readily enough in the summer of 1846. My 

 attention, indeed, was turned more particularly to the point at 

 an earlier portion of the year, when it was difficult to get more 

 than one or two infected leaves, and even had it been possible to 

 collect the spores in any quantity, experiments seemed more 

 likely to give a speedy result if directed to some cereal parasite, 

 such as bunt. The spores are of a peculiar structure, of suffi- 

 cient magnitude to be easily observed, and the mycelium pro- 

 duced of considerable size, and as the disease was to be developed 

 ultimately in a particular organ, to the production of which the 

 ultimate energies of the plant were directed, there seemed a good . 

 chance of being able to observe the progress of the mycelium. 

 I hoped then to ascertain whether the actual penetration of the 

 mycelium into or amongst the tissues of the plant were necessary, 

 or whether the grumous contents of the spores, if circulated 

 amongst the juices, might not be sufficient for its propagation. 

 The latter notion had been lately advanced as a mere theory by 

 Dr. Greville, and I felt inclined to believe, from various observa- 

 tions and considerations, that there was some probability at least 

 about it. The importance of obtaining, if possible, correct 

 information on the point is at once obvious. 



Having determined then to direct my attention to bunt espe- 

 cially, 1 procured as good a sample of wheat as possible, and 

 divided it into two portions, washing the one carefully, and then 

 sowing it with every precaution, that there should be no contact 

 with any of the spores of the bunt with which I was experi- 

 menting ; the other portion was steeped in a thick mixture of 

 bunt and water, a portion of the black liquor being poured on 

 the surface of the soil after the impregnated grains were sowed ; 

 the progress of the grains and spores was then daily examined. 

 The clean wheat sprang up as usual, but there was soon an 

 evident difference in the infected grains, a difference which was 

 distinctly visible till the ears were perfectly developed, when 

 every infected plant was bunted, while from the unimpregnated 

 seeds not a single bunted ear was produced. In one of the 

 bunted plants not only the ear was diseased, but there was a 

 streak of bunt upon the stem, in which the fetid smell and 

 peculiar structure were not to be mistaken, a circumstance which 

 I have never before observed, nor am I aware that the fact has 

 been noticed by others, and confiimatory of the opinion that the 



