28 THE SCOTTISH BOTANICAL REVIEW 
namely, temperature, moisture, precipitations, lighting, wind, etc., 
the conditions of soil and atmosphere ; in other words, the climate 
varies with latitude, altitude, aspect, and exposure. Man has but 
little power to ameliorate the atmospheric conditions, but he often 
does the opposite by allowing air to become polluted by smoke and 
poisonous fumes, thus producing conditions highly inimical to plant 
life.’ On the other hand, something may be done to ameliorate 
the soil conditions. For example, by draining, manuring, and 
cultivating. As regards altitude, exposure, and aspect, man can 
select and cultivate species or varieties in those localities or 
situations where each 1s likely to find the nearest approach to its 
optimum conditions. 
The organic environment is supplied by the plant and animal 
kingdoms. In the vegetable kingdom we have plants in competition 
with one another for the best soil and air space. We have also 
the saprophytic and parasitic forms. The soil bacteria are not 
the least important members of the organic environment, although 
mentioned last. 
The science of Mycology is of the greatest importance in pure and 
applied botany. Fungi play a very important réle in nature as 
saprophytes and parasites. Many forms have by careful selection 
and cultivation been pressed into the service of man in such 
important industries as cheese-making, bread-baking, wine and cider 
preparation, brewing, distilling, etc. 
The cultivated mushroom and the numerous wild edible forms, 
only too little known, have their importance as food plants. Finally, 
the study of the parasitic disease-causing forms is of the highest 
theoretical and economic importance. 
Pure science in investigating the effect of disease aims at 
discovering the changes of the living substance and tissues. It 
may be called Cytopathology. Applied science considers the 
influence of disease on the plant as regards its economic value. We 
must combine both in order to understand the phenomenon from an 
economic standpoint. 
The fungi, bacteria, and insect enemies of cultivated plants cause 
enormous damage and annual loss, not only to the cultivators of 
plants, but to the nation as a whole. 
In Prussia the Phytopathological Commission gave in 1893 a 
striking example of the loss caused by grain-rust. The data were 
supplied by the Prussian Statistical Bureau, so that the figures are 
official. In 1891 the wheat harvest amounted to 10,547,168 
doppelcentner, which at 22 marks per dc. would have amounted 
to £11,459,690, but 3,316,059 dc., or £3,595,758, fell to be 
deducted through depreciation by rust. From the rye harvest 
had to be deducted 48,896,364. Similarly, from the oat harvest 
had to be deducted £8,138,023. Hence the loss on a single 
1 The question of smoke and fume damage to plants is receiving greater 
attention than ever on the Continent. Such damage has increased enormously 
with increasing industrial development. 
