MAMMALIA 241 



Probably the most commonly used poison is powdered white ar- 

 senic which is cheap but is not so effective as some of the others. It 

 is used in various ways, the easiest being to rub it into fresh fish or meat, 

 spread it upon buttered bread, or make it into a dough with corn- 

 meal and white of eggs (i part by weight of arsenic to about 12 

 of cornmeal). 



A better poison is barium carbonate, which may be used in about 

 the same way as the arsenic, except that a larger proportion (i to 4) 

 of the poison is used in making the dough. Its action is so slow that 

 rats often escape from buildings before death, so that it may sometimes 

 be safely used in dwellings. In the small quantities used for rats it 

 is not usually fatal to domestic animals. 



Strychnin (usually as the sulphate) is one of the best poisons for 

 rats but it is so violently poisonous that it should be used with extreme 

 care. Tiny pieces may be inserted in small pieces of meat, or oatmeal 

 or other grain may be soaked over night with strychnin syrup, made 

 by dissolving half an ounce of the sulphate in a pint of boiling water and 

 stirring in a pint of thick sugar syrup. 



Phosphorus is used very commonly as a rat poison, but owing to 

 the fact that fires have frequency been caused by its use it is not to be 

 recommended. It is often claimed that certain of the phosphorus 

 poisons " embalm" or dry up the bodies of rats so that they have no 

 odor this statement is not true of phosphorus nor probably of any 

 other known poison. 



In laying poisons for rodents it is important that they be placed 

 well down in the burrows or be hidden so that domestic animals may not 

 get at them; this is particularly true about stables, chicken houses and 

 such places. A very good way to lay poison, so that chickens and 

 other animals cannot eat it, is to put the poisoned food in a small, 

 upturned box and invert a larger box, in the sides of which small holes 

 have been cut, over the smaller one. 



For killing rats in ships and sometimes in storehouses and other 

 places fumigation is often very effective. In such places sulphur 

 dioxid, chlorine, carbon monoxid and hydrocyanic acid are the gases 

 most frequently used. Chlorine because of its bleaching properties, 

 carbon monoxid because of its lack of odor, and hydrocyanic acid 

 because of its extreme danger to human life are all objectionable; so that 

 sulphur dioxid is perhaps to be most recommended, though it has some 



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