998 VETEEINAEY HYGIENE 



We have seen in Horse Sickness how valuable altitude 

 is, even a relatively small rise may be sufficient to secure 

 comparative immunity. 



In dealing with the question of heat it was pointed out 

 how very rapidly the body by its mechanisms adjusts itself 

 to a rise in external temperature, and though animals 

 from cold countries feel the heat on introduction to hot 

 climates, they very soon, in the course of a few months, 

 become perfectly adapted to their new surroundings. If 

 the transit is from cold northern to southern latitudes, the 

 abrupt transition from winter to summer is felt in the case 

 of horses, mainly, perhaps, owing to the presence of the 

 heavy winter coat. It would a|)pear that it frequently takes 

 from one to two years before the change in the coat is 

 properly established, and there are many observers who 

 regard this, and with a good show of reason, as an index to 

 acclimatization. It takes the Australian horse at least a 

 year to become acclimatized in South Africa, though it 

 involves no transition from one season to another. It takes 

 the same horse two years to be acclimatized to India, where 

 a change in season is involved, and far greater heat 

 experienced. In both these cases the change in food must 

 also be taken into account, though this is much more 

 easily adjusted than the other surroundings. 



During wet and hot seasons in tropical and subtropical 

 countries, horses are certainly not at their best, and this is 

 probably explained as the result of the languor which heat 

 and moisture combined are capable of causing. 



Wounds are liable to take on an unhealthy appearance, 

 and the specific indolent ulcer of India, known as Bursattee, 

 is essentially a wet-weather product, though this and allied 

 sores may yet be shown to be parasitic. 



There is still a more complex aspect to acclimatization. 

 Animals may inherit an immunity to indigenous diseases 

 from which the the newcomer suffers. For example, it is 

 practically impossible to produce Biliary Eever in the 

 native horse of the Transvaal, they are protected by a 

 natural immunity while a foreign horse can be infected 

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