PRESIDENTIAL ADDRESS. 767 
I have now reached the end of my survey. I recognise that it is very 
incomplete, and that I have been compelled to neglect whole subjects in which 
important work has been done. I venture to hope, however, that my words 
have not been altogether unprofitable. It is somewhat difficult to summarise 
what is in itself really nothing but a summary. Perhaps, however, I may 
be allowed to point out once more what appears to me to be the moral of the 
last twenty years of work in agricultural science. 
The many practical fields and feeding tests carried out all over the country 
have demonstrated several very striking results; but, if they are to be con- 
tinued with profit, more trouble must be taken to insure accuracy. Farmers 
are ready to listen. It behoves us more than ever to found what we tell them 
on accurate results. 
Besides such practical trials, however, much has been done in the way of 
individual scientific work. The results thus obtained, as, for instance, Russell 
and Hutchinson’s partial sterilisation of soils, Biffen’s new wheats, and Beaven’s 
pure Archer barley, are of practical value to the farmer as immediate as the 
most practical field trial, and of far wider application. 
The following Papers were read :— 
1. German Forestry Methods. By Professor Fraser Story. 
2. Further Observations on the Fungicidal Action of Bordeaux Mixture. 
By Professor B. T. P. Barker, M.A., and C. T. Gruincuam, FJ.C. 
In a previous paper the authors concluded that probably the most important, 
although not necessarily the only, cause of the fungicidal action of Bordeaux 
mixture is the solvent action which fungus cells under certain conditions are 
capable of exerting on the insoluble copper compounds of the spray fluid. 
In continuation of the earlier work, it has been shown that germinating 
spores and the thin-walled cells of fungus hyphe when in contact with or 
within a limited radius of particles of the copper compounds exercise solvent 
action and are killed by absorption of the dissolved copper. Similar results 
occur in the case of roothairs and the thin-walled external layers of cells of the 
roots of germinating seedlings. The extent of the action depends on the 
character of the cell-wall, apparently according to the degree of permeability. 
In the case of apple leaves, the cuticle of the upper epidermis during spring 
and summer seems to be practically impermeable, and as a result no injury 
fellows spraying so long as the cuticle constitutes a continuous uninjured 
covering to the leaf. If any injury causes a break in it or if a change in its 
character leading to greater permeability occurs—as appears to be the case in 
autumnal foliage—scorching due to injury of the thin-walled internal tissues 
follows owing to direct solvent action of exuded substances on the fungicide. 
While absorbed copper causes death of individual cells or local groups of cells 
in such cases, appreciable amounts of copper may be translocated from the 
affected areas to other parts of the plant without causing injury in transit. 
There is also evidence that copper slowly absorbed through comparatively 
difficultly permeable external walls may be diffused through the plant without 
visible injury to any cells. 
As to the nature of the substances exercising solvent action, in the case of 
germinating seeds and the roots of young plants carbon dioxide is an active 
agent, but in addition other substances not at present examined in detail play 
an important part. 
The physiological effect of the absorbed copper on the treated plant is under 
myestigation. 
3. A Peculiar Disease of Cereals and Roots and the Action of Sulphur 
and Lime. By Wauter E, Counce. 
The disease, which is locally known as ‘ maysick,’ is most evident on wheat, 
and is probably due to bacteria that interfere with the nutrition of the plant. 
