REPORT OF THE CHEMIST. 179 



The strychnine or the strychnine sulphate, as the case may be, should first be 

 powdered. This may be accomplished with a knife blade, piece of iron, or a glass bottle 

 sped as a roller. Use a sufficiency of hot water, and, when the poison is entirely dissolved, 

 pour the solution (of which there should be a large enough quantity to cover the grain) 

 used the wheat. Allow the whole to stand for at least 36 hours, or until the grain has 

 become quite soft, showing that the strychnine has permeated the substance of the wheat. 



A teaspoonful of the poisoned wheat placed at the mouth of each burrow, should be 

 an ample quantity. 



Strychnine is an intensely bitter substance even in very dilute solutions, and no 

 doubt the gophers are often deterred from eating the grain by tasting the poison on the 

 outside of the wheat. Numerous correspondents have written to the effect that they 

 cannot get these pests to touch the bait. Though I have never had the opportunity to 

 try its efficacy, I would suggest sugar coating the pills — in other words sprinkling the 

 poisoned and damp wheat with sugar. 



To recapitulate : Care should be taken to see, in the first place, that the strychnine 

 is all dissolved ; and secondly, that the grain has become soft, showing thorough satu- 

 ration with the poisoned liquid. 



Of course the greatest care must be exercised when using strychnine, in order that 

 children and farm animals may run no risk of poisoning. 



Carbon Bisulphide as an Exterminator. 



A method that is strongly advocated by those who have practised it in the United 

 States is one employing carbon bisulphide. It is held to be cheaper, more efficacious 

 and less dangerous to use than strychnine. 



Carbon bisulphide is a highly inflammable liquid, with a very disagreeable smelL 

 Though not corrosive, its vapour is detrimental to health when breathed in quantities. 

 It, however, can be used without any danger, provided ordinary care is exercised — more 

 especially with regard to fire and flame. 



The method is as follows : Saturate a small ball of cotton waste with the bisulphide, 

 and throw it into the burrow in the evening ; then close the mouth of the hole with a 

 little earth. 



Dry balls of horse manure have been used successfully instead of cotton. 



Respecting this method, I would make two quotations. Dr. C. Hart Merriam, 

 Chief of the Division of Ornithology and Mammalogy, Washington, D.C., writes me 

 as follows : — 



" As a general rule, we do not recommend either arsenic or strychnine for the 

 extermination of pocket gophers. We prefer the sulphide of carbon as cheaper and 

 more efficacious. A handful of rags or waste wet with the bisulphide should be thrust into 

 a fresh burrow ; the mouth of the burrow should then be stopped. The fumes from the 

 bisulphide being heavier than atmospheric air, float down along the tunnel to its remo- 

 test ramifications, destroying all animals there." 



In a letter from Prof. Niswander, of the Wyoming Experiment Station, I have 

 the following testimony : — 



" Over 2,000 burrows have been treated by me in 1893 by bisulphide, and 99 per 

 cent of the trials have been successful 



" In a few instances the holes had been apparently opened from the outside, and 

 these were all counted with the unsatisfactory trials. I have no hesitation in recom- 

 mending carbon bisulphide for burrowing animals." 



Further, he says : — 



" The most important thing in the use of strychnine is to get the gophers to eat it ; 

 with the bisulphide this is not necessary. Both arsenic and strychnine are dangerous 

 to stock running loose, the bisulphide entails no such risk." 



During the early months of this summer, Mr. Mackay, Superintendent of the Ex- 

 perimental Farm at Indian Head, N.W.T., was asked to make some experiments with 



8c— 12£ 



