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THE MONTHLY BULLETIN. 



eradication nor have caused greater interest in control methods 

 than the announcement by Professor E. W. Hilgard of the University 

 of California Agricultural College in 1878 that carbon disulphid 

 absolutely would rid an area of ground squirrels exactly as he had 

 demonstrated on the University of California campus at Berkeley. He 

 argued that of the poisons in the shape of scattered or exposed baits 

 there was grave danger to stock, and further that a good sheep dog 

 might be killed by eating poisoned squirrels. Even danger attended 

 the mixing of such poisons before the person intending to use same 

 should leave the house, where children or poultry could gain access to 

 the mixing utensils. 



Hitherto viticulturists had used carbon disulphid in attempting to 

 control phylloxera on grapevines, and while attending a grape-growers' 

 session in Paris Professor Hilgard learned of its use as an expedient 

 to get rid of rats in sewers of that city. The method of application 

 suggested at first was rather expensive, as it called for pouring a 

 measured amount' into the burrow from some sort of a vial. Professor 

 Hilgard explained the properties of the substance in detail 1 , noting 

 its mode of preparation, that it was heavier than air, and its effective- 

 ness as a fumigant for squirrels. He used about one pound to the 

 acre on an average infestation, which at that time would cost about 

 45 cents. This meant $4.50 per gallon, a price conceded to be too high 

 for general use. All of the carbon disulphid coming to the Pacific 

 Coast was put up in pound containers, had been refined for chemists' 

 use, and although it cost but 12 cents per pound in St. Louis, by the 

 time the express was added the cost was close to 50 cents per pound. 

 The high charge was partly due to the increased rate assessed on 

 account of the danger attending the handling of an explosive substance. 

 In 1879 we get the first suggestion for using wasteballs from Australia, 

 for in that country the method was being tried on rabbits. Wads of 

 cloth were used, over which the carbon disulphid was poured. Uni- 

 formly good results were reported from use in rabbit burrows. To 

 get a manufacturer to undertake the production of carbon disulphid 

 in California was another question, and it was about ten years (1888) 

 before we learn of Wheeler 's carbon disulphid appearing on the market. 



Thus carbon disulphid filled a decided need for a substance which 

 would permit continuous ground squirrel control work throughout the 

 full year. Up to this time poisoned grains were considered the best 

 for all-around work. Professor Hilgard had called to the attention of 

 all interested the fact that this gas was most practical for use in wet 

 ground and that rather a large amount of waste would be entailed 

 when the soil was dry and cracked. The early manufacturer of carbon 

 disulphid recommended the use of a bottle or bucket for carrying the 

 carbon disulphid ; application to be made with a funnel to which a long 

 hose was attached (Fig. 45). We know this to be a very wasteful 

 method, still the success with which the landowners met in using the 

 stuff made them so enthusiastic that cost was in a measure forgotten. 

 The waste-ball plan of using carbon disulphid soon came to be looked 

 upon as a conserver of the liquid, and still later by the invention of the 



'University of California Bulletin No. 23, 1878. 



148 



