INSECTICIDES, PREVENTIVES, AND MACHINERY. 453 



sonous to many kinds of insects, so it may be used to protect 

 against their attacks in stored products. It has been said that a 

 sprinkhng of naphthahne crystals on the surface of grain recep- 

 tacles will keep out all sorts of pests, and no doubt there is 

 more or less basis for this claim. Naphthaline is used to keep 

 museum pests out of boxes and cases containing specimens. 

 Packed with clothing, woollens, or fabrics of any kind in a toler-^ 

 ably tight box or closet, it will protect them from the attacks of 

 "moths." 



Quassia, in the form of a decoction, has been recommended 

 for insects of various kinds, noticeably plant-lice ; but, in my own 

 experience, the results obtained have been so unsatisfactory that it 

 would hardly pay to recommend it, when the soaps are so much 

 more effective as well as less expensive. 



It remains to say a few v/ords on the subject of patented insect- 

 icides, or mixtures sold under fancy names. As a general rule, 

 such should be avoided. Many of them are more or less merito- 

 rious, but in most instances they are paid for altogether too 

 highly. In some cases the name has covered a mere mixture of 

 Paris green and land plaster, charged for at many times its true 

 value, and then advertised, besides, as being harmless. The 

 range of the insecticides already mentioned will serve almost 

 every purpose required by the farmer, and before using any pat- 

 ented preparation, he should make an effort to ascertain just 

 what material he is applying to his plants. It is also advisable to 

 warn against the plausible schemes for preventing injury to trees 

 and other plants by "inoculation," — that is to say, placing 

 some substance into the body of the tree, with the idea that it 

 will be carried into the circulation to repel insects that might be 

 tempted to feed upon the foliage. All such preparations hereto- 

 fore used have been frauds, and no benefit has ever resulted from 

 any of them. In the same category belong those mixtures into 

 which seed potatoes or other seeds are to be dipped or rolled to 

 prevent the attacks of potato-beetles or other leaf-feeding insects. 



