157 



by the rodent it produces death by the formation of enteroliths, 

 death occurring in from four to eight days. This is a poison of 

 uncertain value and is recommended chiefly on account of its cheap- 

 ness and small danger to children and domestic animals. It can 

 not be used in wet weather, and judging from the small number of 

 rats found dead with plaster casts in the alimentary canal it is not 

 beUeved to be very efficacious. 



PHOSPHOKUS PASTE. 



Phosphorus paste is prepared by mixing crude phosphorus in the 

 proportion of one-half to 10 per cent in a suitable base. The latter 

 may consist of cheese, sugar, and oil of anise mixed together and 

 heated to the consistency of sirup, the phosphorus being added after 

 the fire has been withdrawn and the mixture begun to cool. Other 

 bases are cheese, corn meal, and oil of rhodium; cheese, ground fish, 

 or meat and oil of valerian, glucose, and a small quantity of flour. 

 Glucose makes an exceptionally good base, as when properly mixed 

 the poison thus prepared is noninflammable even when heated. 

 The Hability to spontaneous combustion of phosphorus mixtures 

 eliminates their use in hay, grain, or other warehouses or places 

 where there is danger of fire or the invahdation of insurance. It 

 should not be forgotten that phosphorus deteriorates very rapidly, 

 especially when it is exposed to the sun. 



ARSENIC PASTE. 



This consists of arsenious acid combined with a base of cheese, 

 meal, or macerated fish. It may be placed on raisins or prunes and 

 is to be recommended on account of its stabihty, the ease with which 

 it is handled, and the absence of danger from fire. It should, how- 

 ever, be distributed with great care, every percaution being used to 

 place it where it is inaccessible to children and domestic animals. 



BARIUM CARBONATE. 



This has not proven an effective poison owing to the fact that it 

 is easily decomposed hj the vegetable acids, especially lactic and 

 oleic acid found in cheese and oil. The poisonous effect is not 

 greatly altered by this change. A disagreeable metallic taste is pro- 

 duced and the rats will not take it. 



STRYCHNINE. 



Strychnine is prepared as a poison by soaking wheat over night 

 in water and subsequently pouring off the excess fluid and placing 

 the wheat in a caldron containing hot glucose and strychnia sul- 

 phate, the latter in the proportion of one-tenth of 1 per cent. After 

 carefully stirring so that each grain is thoroughly coated it is dried 



