1898] ON SOME ASPECTS OF VEGETABLE PATHOLOGY 189 
seldom, if ever, obtain in the field. The pathologist must be 
prepared to ascertain and to correct the predisposing as well as 
the apparent causes of disease, and among such causes he may 
even be forced to include the long process of artificial selection 
which has had as its almost exclusive aim the development of 
plants along lines of fruitage only, with too little regard to 
those factors which tend to produce hardy stock resistant to 
unfavorable conditions. 
I make these statements with some hesitation, yet I believe 
them to be borne out by facts. It is becoming more and more 
apparent that in combating the host of fungi which invade our 
orchards and truck farms in these days of intensive farming, due 
gard must be paid to what we may call the hygiene of plant 
- The proper regulation of the water supply by drainage and 
tillage ; the securing of the free access of air and sunlight by 
Se, § thinning, and training; care in the selection of healthy, 
resistant stock; the intelligent use of fertilizers and their adap- 
‘ation to the needs of the plant —these are some of the sanitary 
Measures which, duly considered and acted upon, will do more 
than the mere use of fungicides to insure success in dealing with 
fungous diseases, 
— = individual proofs of these general statements: Experi- 
his hee cently conducted at the Rhode Island Experiment Sta- 
celery a far to show that the two most serious diseases of 
ciated an ue, not primarily to the attacks of the fungi asso- 
among So eae though both of them might properly be placed 
the plants a s ‘ Schwiche-Parasiten,” but to a weakening of 
culture oe to the purely artificial level method of 
ei ed the roots are exposed to all the temperature- 
leaves of as Surface soil. A mulch, consisting even of the 
iN question sag celery teeming with the spores of the fungi 
Proper attenti tved to prevent the spread of the ISEREE That 
ease the on to purely cultural conditions will very largely 
bservation SSeabg of apple ‘‘scab” is a matter of common 
the st and T have myself seen a peach orchard, showing 
Ymptons of a serious attack of Cercospora Persia, com- 
