No. 4.] RATS AND RAT RIDDANCE. 225 



as reliable and effective as any poison. Professor Lantz writes 

 me, however, that the Public Health Service, since distributing 

 poisons at San Francisco and New Orleans, has become con- 

 vinced that arsenic is a very unreliable rat poison. Never- 

 theless, it has been used effectively for this purpose for more 

 than a century. On Thompson's Island, in 1907, when the 

 rats had become so numerous that they were destroying every- 

 thing edible on the farm, they were reduced almost to harmless 

 numbers at once by quantities of ground fish and arsenic 

 and sandwiches composed of bread, butter and arsenic. Five 

 hundred pounds of fish and 50 loaves of bread were used. 



Arsenate of copper, in the form of Paris green, which is 

 much used as a commercial rat poison, has no advantage over 

 white arsenic, except that of color, which renders it con- 

 spicuous, but it has the disadvantage that it contains less poison 

 to the pound, and most of the commercial Paris green is 

 adulterated. Arsenate of lead is a slower poison, of less 

 strength than white arsenic, and though now much used it is 

 not recommended. London purple has the advantage of con- 

 spicuous color. Arsenate of soda has not been used as rat 

 poison so far as I am aware White arsenic is a very dangerous 

 poison in the hands of a careless person, as it somewhat re- 

 sembles flour; it may be bought at a low price by the pound 

 from wholesale druggists. A time-honored way of administering 

 arsenic to rats is to place pieces of bread and butter sprinkled 

 with sugar near their runs night after night, until they have 

 learned where to look for them and their suspicions have been 

 allayed, then to spread finely 'powdered arsenic thinly over both 

 sides of slices of bread and spread 

 soft butter over the arsenic, or, 

 better, mix arsenic with the butter ^ 

 before spreading, and sprinkle with c^!i^^;\^^* 



sugar as before. The poison be- Pain and apprehension. 



comes incorporated with the butter, 



and is eaten without suspicion by the cunning rodents. Some- 

 times, however, the sly rat will eat the bread and avoid the 

 poisoned butter, and it is better to melt the butter, stir in 

 an equal quantity of arsenic, and pour the mixture on both 



