SOME MODERN ASPECTS OF APPLIED BOTANY 35 
scientific training. Many of these local representatives are clericals, 
schoolmasters, leading agriculturists, etc. Their principal duty is 
to send in reports on specially prepared schedules to the Central 
Institution as nearly as possible every four weeks. Each local 
station has in turn correspondents (Vertrauensmanner) in as many 
country districts as possible. These correspondents are, so to speak, 
the men on the spot, and they are constantly in touch with the local 
agents, and thus the Central Institution is kept constantly informed 
regarding the state of field and garden crops all over the country, 
and, should occasion arise, experts can at once be sent to investigate 
and advise. ‘The Imperial Biological Institution for Agriculture and 
Forestry situated at. Dahlem, near Berlin, is the principal institution, 
and is kept posted up to date from all the other Central Institutions 
of the empire. 
The ceaseless activity of these institutions has already resulted in 
the accomplishment of an extraordinary amount of useful work of 
the highest scientific importance and economic value. 
As a Society, we cannot hope to deal with problems in applied 
botany On the same scale‘as a well-organised and subsidised State 
Department, but, nevertheless, we could be of some use I think. 
We have Local Secretaries and members almost all over the country, 
and no doubt many would be quite willing to make systematic 
observations on the occurrence, spread, and severity of plant 
diseases in the forest, field, and garden of their own particular area. 
Doubtful cases of any disease, the cause of which was not evident to 
the local representative, might be sent in to headquarters, where a 
Special Committee might investigate and report. The reports and 
records of the Local Agents and those of the Central Committee 
would in time become not only of scientific interest but of great 
practical utility. 
The making and recording of these observations may seem all very 
simple and such as anyone might be able to make, but I do not 
propose for one moment that such records should contain a mere 
list of parasitic fungi found from year to year; such lists alone would 
have very little scientific or practical value, 
These investigations could only be carried out by botanists. 
They would have to be of the nature of an cecological study of the 
disease. Such factors as the influence of the soil, the climatic 
influence, the local method of cultivation, the nature of the attack— 
slight or severe—the presence of other plants, in fact all the condi- 
tions in the physical and organic environment which influence the 
relationship of host and parasite would be noted and recorded. It 
is only by such means that we can gain any clear and definite 
knowledge of the conditions in nature which influence the increase 
or decrease of disease. It is only when we are in possession of such 
records that prophylactic measures can be evolved, and plant hygiene 
placed upon a sound scientific basis. 
The complete study of a plant disease may be presented as 
follows :—First, we should learn to diagnose the disease from its 
