REFLECTIONS ON DISEASE TREATMENT 195 
All available information should be obtained and every 
detail followed minutely. 
Resistant Varieties 
The employment of such varieties as are highly 
resistant to disease is the simplest way of guarding 
against it, and where disease is rampant these varieties 
should be grown when possible. Unfortunately the 
number of resistant varieties of cultivated plants is very 
limited, but it is in the interests of the country that no 
money should be spared in obtaining a great many more. 
The usual criticism against employing resistant varieties 
is that such are lacking in quality and productiveness. 
This fact must be borne in mind by every hybridist, so 
that resistant varieties of high commercial value may 
be produced. ; 
Finally, a word to pathologists and students of 
disease problems, the outcome of much experience in 
commercial nurseries. First learn to grow your plants 
so that they may pass the most critical examination for 
health, quality, and productiveness by practical com- 
mercial growers, and then experiment upon the healthy 
plant. It is useless to base detailed knowledge of any 
disease or the method of its control on experiments 
conducted on half-starved, physiologically weak plants 
grown in tiny pots. 
