304 NATURE-STUDY REVIEW [16:7— Oct., 1920 



We do not need to be reminded that the teaching of plant 

 diseases in any organized way is very recent. The Yearbook of the 

 Department of Agriculture for 1899 tells us that in 1885 there 

 were only three institutions teaching this subject and that ten 

 years later "50 colleges and stations engaged in the work and at 

 least 100 special investigators were devoting their time to it." 



Notwithstanding these preliminary remarks there are sufficient 

 reasons for introducing the subject at this time. In Massachusetts 

 alone for the summer of 19 18 it is reported that 75,000 boys and 

 girls not living on farms had gardens. If they are to be encouraged 

 in this work they must know how to take care of these diseases 

 which are so prevalent. Then, again, the potato blight is not a 

 concern of Maine alone nor the black wart of the potato, in Penn- 

 sylvania, just a question of that state. There must be a Federal 

 intelligence in regard to the things which concern its welfare. 

 Likewise, a healthy garden is a community asset, and the ignorance 

 of one gardener is a menace to the whole neighborhood. Other 

 by-products of this knowledge will be a greater intelligence in 

 regard to the causes of all diseases and their cure by patent medi- 

 cines. Then, the consumer should have an appreciation of whole- 

 some food and knowledge as to how it should be cared for in the 

 home. He should have some notion as to what it costs to grow 

 clean healthy produce and a greater respect for the farmer. A far 

 more important result may be the plant physician for every com- 

 munity. He will work after the fashion of the Chinese doctors 

 who are paid for the prevention rather than the cure of diseases. 

 In this way the working power of the gardens of the community 

 will be kept at top-notch efficiency. 



If plant diseases should be taught in the grades what are some 

 of the topics that may be presented and what method ought to be 

 used? The following notes are merely suggestive as to a few 

 projects. 



Cut slices of raw potato with a sterilized knife and place each 

 slice in a saucer under a glsss. Place under different conditions, 

 such as: warm, cold; dry, moist; sunny, dark; a slice that has 

 been in contact with a dusty surface and one that has not ; peeled 

 and unpeeled ; a healthy potato in contact with a decaying spot on 

 another potato, and a healthy potato in contact with a healthy 

 potato; a bruised and a scratched potato and a sound potato. A 

 child can easily derive the following practical conclusions by 



