62 



HEALTH AND DISEASE 



has only been averted by the introduction of a tube into the trachea (see 

 Tracheotomy). The stings of most poisonous insects have an acid reaction, 

 and treatment on the lines above indicated will usually be found successful. 



HAY 



Cases of poisoning due to hay feeding, crop up from time to time. 

 Now it is Dutch, and next Canadian, but mostly foreign food-stuffs that 



cause illness in horses in this 

 country. The deleterious in- 

 gredient has not always been 

 traced, but it would seem 

 that animals bred upon a 

 particular pasture gain im- 



Fig. 460. — Colchicum autumnale 



Fig. 461.— Alfalfa (Medicago saliva) 



munity from the effects of herbage which causes illness in others, or else 

 develop a power of selection which enables them to reject certain poisonous 

 plants even when compressed in form of hay. 



In the low pastures of Flanders we have seen much colchicum (fig. 460) 

 growing, and observed that native stock carefully avoid it, but when made 

 into hay and imported into this country it may be that animals in our 

 great cities, drawn from all sorts of sources, are not able to distinguish it. 

 The dry, hard grasses, chiefly alfalfa (fig. 461), upon which American 



