168 M. C. COOKE ON BUNT SPORES. 



fully, 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 

 experimenting ; the other portion was steeped in a thick mixture 

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

 the sui'face 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 con- 

 firmatory of the opinion that the disease is not a mere alteration of 

 structure in the grains of fecula, were such testimony wanted, 



" Four days after sowing I found that the spores of the Uredo 

 [Tilletia) had been sucked in, doubtless by capillary attraction, 

 between the yonng root and its investing membrane, which was 

 ruptured, germination at that period having scarcely taken i^lace. 

 The spores were quite as large as either of the two distinct series 

 of cells of which the young root is composed. 



" Three days later I perceived the first traces of germination in 

 the spores. A little obtuse tube, thicker than the pellucid border 

 of the spores, in a very few instances only, and appearing like a 

 short peduncle, scarcely so long as their diameter, was protruded 

 through the external membrane. This surprised me extremely, 

 because on the mass of spores, whether on the surface of the soil or 

 on the grains of wheat, there was a white, very delicate, extremely 

 short down. On a closer examination, the greater part of the 

 grains of bunt were found to be clothed on one side, with fascicles of 

 white filaments, from two to four times longer than the diameter 

 of the bunt spores, and producing towards their apices extremely 

 long and slender, somewhat curved, acuminate, multiseptate spores. 



" Three days later a large portion of the grains of bunt were 

 ruptured, either irregularly or in a stellate form ; a few more had 

 germinated, the filaments being evidently protruded from the inter- 

 nal membrane, and either straight or curved, and occasionally 

 branching off in two opjDOsite directions, the tips of the threads 



