276 VETEEINAEY TOXICOLOGY 



may be vermilion or red lead ; heavy black particles may 

 be antimony sulphide. It is only rarely that colour is 

 detected, for in most cases the dilution of a coloured poison 

 in such a mass of green ingesta as is found in the stomach 

 of the ox is too great for its recognition. With smaller 

 animals the indication is more valuable. 



Smell. — Compounds, easily recognisable by their smell, are 

 phosphorus, hydrocyanic acid, alcohol, ether, chloroform, 

 carbolic acid, savin, turpentine, essential oils, ammonia, 

 and sulphuretted hydrogen. The two last are often pro- 

 ducts of decomposition, and caution is needed on this 

 account in forming an opinion. In general the smell is 

 difficult to observe on account both of the natural and 

 putrefactive smell of the viscera. 



The odorous substances fall into Group A of the volatile 

 poisons, and their smells are best observed in the course of 

 analysis for that group. 



Suspicious particles and vegetable fragments ought to be 

 carefully looked for and picked out. Valuable guidance is 

 thus given, and in the case of many, or most, poisonous 

 plants the finding and identification of vegetable detritus 

 gives the best chance of correct diagnosis. 



It is a good plan to stir up the semi-solid contents to a 

 thin paste with water, and, after standing, carefully decant 

 from heavy particles, which (if found) may' be washed with 

 a gentle stream of water. Particles of such substances as 

 white arsenic, black antimony, vermilion, red lead, and 

 white lead, may thus be separated. 



In the case of dogs and foxes the nature of the stomach 

 contents ought to be ascertained as far as possible. This 

 gives very valuable information in tracing the source of 

 poisoning. With these animals the presence in the stomach 

 of scraps of fur, small bones, or feathers, usually points to- 

 a bait of rabbit dr bird, which has been the vehicle of the 

 poison. 



Disposition of the material for the special analyses is a most 

 important point, which is best left to discretion. The analyst 

 must be guided entirely by considerations arising from the 



