■Inlrihliii-flon. 7 



spores wiiicli would not fiortniualc at all did so without (wccptioii. It was 

 further discovered that the genniuatiou went beyond that which occurred in 

 water and was not only more luxuriant, but that instead of stopping at that 

 stage, the secondary spores or conidia began to sprout on their own account. 

 These sprouting conidia as they are called by Brefeld, continued to multiply 

 indefinitely as long as the nutrient material lasted, and, becoming detachecl, 

 continued the process just like yeast-cells. Some of these sprouting conidia 

 had also the capacity of giving rise to aerial conidia, which, on account of 

 their minuteness, were scattered in immense numbers by the wind. The 

 final step was taken when infection was proved to t^ke place, not oidy in the 

 seedling, as in Stinking Smut of wdieat, but also n the }'oung and tender tissue 

 of developing maize plants as in the American Corn Smut, and in some cases, 

 in the flower itself. This floral infection was first practically demonstrated 

 and described in 1896, by Maddox.in the Tasmanian Agricultural Gazette, and 

 afterwards re-discovered, in 1905, by Brefeld.^ The probabilities are, that 

 some host-plants are capable of infection both through the young seedling 

 and the flower, but that has yet to be proved. 



Hitherto, it was taken for granted that the parasitic fungi could only live 

 and grow upon the particular host-plants with which they were associated in 

 nature, and that it was only by confining observations and experiments to 

 the host-plants that the full course of their development could be traced. 

 f But Brefeld opened up a new field of inqub:y when he showed, in the most con- 

 vincing manner, that parasitic fungi can live outside of the host-plant, and 

 that in nutrient solutions they could grow as luxuriantly and sometimes even 

 . more so than they did on their natural hosts. While the smuts can maintain 

 themselves on the living plant, they are also capable of existing on dead 

 organic substances, and thus the line of demarcation between parasites and 

 saprophytes was shown to be less rigid than commonly supposed. In fact, 

 there are sources of infection quite outside the host-plant which have to be 

 taken into account when considering the propagation and prevention of 

 snmt. 



Each successive step in advance has thrown fresh light upon what takes 

 place in nature, and the discovery of infection through the flower has explained 

 how it is that in Loose Smut of wheat, and Naked Smut of barley, disinfection 

 of the seed has not been successful in preventing the disease, and how the 

 smut may break out in places where it has never before been known, through 

 being carried in a dormant condition within the seed, even although that seed 

 had been carefully treated and there were no wild or cultivated grasses in the 

 neighbourhood from which it might have been derived. 



