222 FUMIGATION METHODS 



The following letteis or quotations from scientific 

 and practical men who have either used hydrocyanic 

 acid gas or are thoroughly familiar with its properties 

 and economic values are interesting in this connection. 

 We have alluded to the early history of the discovery 



FIG. 82 FUMIGATED CITRUS 



Orchard of J. W. Henderson, near National City, California, only a 

 short distance from the Stearns ranch, on which Fig. 83 was 

 taken. Orchards about the same time. Note the difference. 



of the gas as an insecticide in Chapter I. There seems 

 to be some misunderstanding as to its first application 

 to nursery stock. In the "Year-Book of the United 

 States Department of Agriculture for 1899," Dr. L,. O. 

 Howard, Entomologist, is of the opinion that he first 

 recommended the use of hydrocyanic acid gas as a dis- 



