8 FUMIGATION METHODS 



and the box system, designated by me as the " Kmory 

 Fumigator," has been perfected, and is now commonly 

 used by orchardists and others. 



Since 1894 the g as nas a l so been used in green- 

 houses for the destruction of certain pests. The 

 demand for fumigated trees led me to conduct an 

 extensive series of experiments with the gas upon 

 nursery stock of various kinds and grades. These 

 tests, begun the fall of 1896 and completed the spring 

 of 1899, have shown conclusively the maximum and 

 minimum amount of gas young trees will withstand 

 without injury. Many obscure points about the con- 

 struction and management of fumigating houses have 

 been made clear. 



In 1898 I first suggested the use of hydrocyanic 

 acid gas as a remedy for the destruction of insects in 

 mills, elevators, and warehouses. The system has 

 since been perfected under my direction, and it is now 

 in general use in this and other countries. In 1900 I 

 demonstrated that the gas could be used in tight 

 buildings with perfect success and .safety, even in the 

 thickly populated districts of a city, w T hen properly 

 handled, for the destruction of certain pests, including 

 rats and mice. The fumigation of street-cars and 

 railroad coaches to destroy bedbugs and other vermin 

 is commonly practiced in many places. The gas is 

 also employed to rid houses of undesirable pests, but 

 in such cases should be handled with great care. 



