96 SMUT IN WHEAT. 



have proved that the fungus is only able to effect an entrance 

 to its host by attacking, the embryonic tissue; once inside, it 

 gradually permeates the whole plant, extending with its growth 

 fi'om cell to cell, and finally meeting in the young fruit con- 

 ditions favourable to the production of spores. As the fungus 

 can only enter the tender tissue at the color of the young seed- 

 ling, it is very important that the cultivator should endeavour, 

 by the selection of good, sound, clean seed only, and a good and 

 properly prepared seed bed, to encourage a rapid growth from 

 the first. Anything that tends to retard this growth in its 

 earliest stages lengthens the time during which it is possible 

 for the fungus to effect an entrance, and greatly increases 

 the chances of infection ; a few hours even may make all the 

 difference, for though thousands of sporidea may be near the 

 color of the young seedling, no entrance can take place unless 

 the germ tubes reach it at the critical time. Experiments 

 have been made with a view of infecting the leaves and stem 

 of the growing corn with the germinating spores, but have 

 invariably resulted in failure, except on the tender growing 

 point, where the tissues remained sufficiently soft for the 

 sporidea to effect an entrance, but under natural conditions 

 this point is not subject to attack. As regards suit- 

 able dressings, there is yet a large field open ta 

 investigators ; if freeing the seed coat from spores super- 

 ficially attached was all that was necessary, the matter would 

 be simple enough, but much more than this is required, as 

 the smut fungus may be present in the soil itself, ready to 

 attack the grain at the critical time. Dressings, to be 

 effectual, must be sufiiciently permanent to destroy in the soil 

 any prymocelia or conoidal cells that may happen to be in 

 proximity. with the seed corn. The following are said to be- 

 as efiicacious as any at present known : — A strong solution of 

 Glauber's salts, in which the seed grain is to be well washed, 

 and afterwards, while still moist, dusted over with quicklime ;. 

 by the application of the lime the caustic soda is set free and 

 destroys any fungoid growths it may come in contact with. 

 The application of copper sulphate to the grain as a dressing 

 before sowing is a well-known remedy, but though it destroys 

 the fungus it greatly retards the growth of the wheat, which 

 is an objection to its use. Lime applied after the copper salt 

 neutralises its prolonged effect, and is a good practice. The 

 presence of lime itself in the soil is likewise beneficial. The 

 foregoing notes are the result of the labours of many com- 

 petent investigators, who have bestowed much time and care 

 on the subject, the elucidation of which necessitated thousands 

 of artificial cultures of the fungus and microscopical examina- 

 tions. One or two points in Mr. Joseph Barwick's 

 communication will be better accounted for, if viewed with the- 

 light thrown on the subject by recent investigations. Mr.. 



