13^ The yoiirnal of Forestry. 



lu choosing the kind of poison we must seek to combine, as far as 

 possible, the following qualities : — 

 {a) Cheapness. 



(&) The power of attracting the rats. 



(c) Speedy action, so that a small quantity is sufficient to cause loss 

 of appetite and eventual death, 



id) The power of resisting the decomposing influence of air and 

 moisture. 



ie) The property of converting the dead rat itself into poison for the 

 other rats, which are known to feed upon their dead comrades. 



(/") As the young sowings will eventually be reopened for cattle grazing, 

 the poison should be of such a kind that in the course of time its poisonous 

 property will disappear, that the cattle may not suflFer. 



The kind of poison which best fulfils all these conditions, except the 

 first, appears to be strychnine, but as strychnine is expensive, it can only 

 be employed in nurseries, and not in the open sowings. 



Next to strychnine, phosphorus is the best poison, but it is apt to 

 deteriorate through exposure. 



Arsenic (arsenious acid, or white arsenic) is less speedy in its action than 

 phosphorus, but resists the action of the air better. 



If a mixture of phosphorus and arsenic is used, the advantages of both 

 are combined. 



As our writer lays great importance upon the method of preparing the 

 poison, I will give the directions in his own words. " The proportions of 

 the ingredients are — 



Flour 1-00000 parts. 



Wheat 1-00000 „ 



Phosphorus 01209 „ 



White arsenic 001101 „ 



Water 0-46591 „ * 



" The water should be first weighed out and poured boiling hot into a 

 kettle, together with the weighed quantity of phosphorus. This having 

 melted,, one-third of the whole quantity of flour should be added by 

 degrees, and afterwards the difficultly soluble arsenic, the whole being 

 thoroughly stirred. The wheat should now be stirred into the paste thus 

 prepared, and the second third of the flour added. The mass will then be 

 of the consistency of a stiff dough, and should be placed in a flat open box, 

 at which several people can stand and knead the mixture of dough and 

 wheat thoroughly with the remaining third of the flour. This should be 

 done in such a way that the single corns, instead of remaining embedded 

 in the mass, separate from one another, each being covered with a crust 

 of the poisoned dough." 



" To escape inhaling the injurious vapours of phosphorus, the workmen 

 should, during the process, keep their heads in the air ; the vapours will 

 sink in the atmosphere, and will then be li armless." 



* The proportions are given in this table in an alarming form. Reduced to English 

 weight, they are for each pound of flour and of wheat, %^.\ grains of phosphorus, 

 77 grains of arsenic, and 8 ounces of water. 



