738 



THE MONTHLY BULLETIN. 



grains. In mentioning the morning feeding of ground squirrels this 

 point is brought to mind, that from the use of cyanide it came to be 

 habitual among many ranchers to expose poisoned grain either late in 

 the evening or early in the morning, for it evidently had been learned 

 from experience that cyanid was volatile in the atmosphere, rapidly 

 decomposing and leaving the grain. Unless exposed with the view to 

 having it consumed within twenty-four hours grain should not be used 

 unless with strychnine, which will remain to render the poison effective 

 for a long period, provided it is not washed away by heavy fogs or 

 rains. The use of gum arabic to form a moisture-resisting coating 

 substance in which strychnine had been dissolved was used as early as 

 1877, but did not come into general use. In later experiments upon 

 poisoned grain this gum was used to learn if it would make possible 

 the use of a coated grain bait throughout the rainy season. 



Of all formulas in use prior to the advent of our present perfected 

 one 1 , the exterminator termed " dead-shot" seems to have had general 

 approval. When the Board of Supervisors of Tulare County appro- 

 priated $500 for each supervisorial district, it was this formula that 

 was to be followed to the letter inasmuch as the satisfaction it had 

 given proved it to be a worthy article. Essentially the ingredients 

 were wheat, 25 pounds; or barley, 30 pounds; strychnine crystals 

 (sulphate) 1 ounce; cyanid of potassium, 1 ounce; strained honey or 

 syrup, 1 quart; water, 1 gill; peppermint, 5 drops; anise oil, 7 drops, 

 with a little oil of rhodium or cummin thrown in. Interesting devia- 

 tions from this were noted, still all ingredients used differing in kind 

 or quantity gave essentially the same result in the end. 



In general for all formulas pennyroyal, anise, rhodium, peppermint 

 and cummin were used for scent. A suggestion found in one article 

 leads to the belief that pyroligneous acid might have been used in this 

 connection inasmuch as it would give the flavor or scent of smoke. 



For sweetening almost anything or everything producing a sweet 

 taste was used — black molasses, sorghum, maple, corn or sugar syrup, 

 strained or comb honey, brown sugar, white sugar and powdered sugar. 

 The use of saccharin did not come into vogue until a considerably later 

 date. It was noted that it was not necessary to soak the grain in 

 strychnine, but that any coating which would hold the strychnine 

 served the purpose admirably. The media for this were mostly flour 

 pastes and syrups, white of egg, starch paste, gum arabic and rice 

 paste. The perfecting of these various ingredients as to quantity and 

 kinds was later done by Mr. S. E. Piper of the U. S. Department of 

 Agriculture, as related in a following article which brings out the 

 details in very good style, stressing reasons for the ingredients being 

 in the formula and why a coated grain is most acceptable. 



This perfected formula came to be known as the Biological Survey 

 formula, and its use over a number of years has proved an efficiency 

 yet to be attained by any formula developed. 



The mention of coated grain calls to mind the carrying of grain in 

 the cheek pouches, the capacity of which has been exaggerated in a 

 great many instances. In this regard we have records taken from the 

 Pacific Rural Press of actual counts, some of which are submitted for 



Appendix, p. 790. 



146 



