266 LYMPHANGITIS. 



result of inflammatory action in connection with botli l}Tnph 

 glands and vessels, is natural and easy. 



The same engorgement, arrest of functional activity, and 

 irritation is as apt to follow any great and sudden change in 

 the habits and work of horses as they are in the case of the 

 supply in excess of nutritive material. This is particularly 

 evident with horses which have for some time been doing 

 good regular work, and receiving a full supply of even whole- 

 some food on a sudden cessation or lessening of the work 

 done. The absorbent and lymph vessels, in such cases 

 regularly and for a lengthened period kept in tone and full 

 activity by the steady muscular contraction and movement of 

 the limbs, and by the regularity with Avhich their contents 

 are disposed of in the regular exercise of animal activity, at 

 once and suddenly receiving a check, engorgement and irrita- 

 tion follow, not because an extra amount of nutritious 

 material may be poured into the system through the primary 

 digestion, but because the activity in the secondary is sud- 

 denly brought to a stand by the non-demand for its products, 

 owing to arrested animal functions. It is in this way that we 

 account for the occurrence of weed amongst our hard-worked 

 full-fed city and town dray and heavy draught horses on 

 Monday mornings. 



Karely in country districts is this disease encountered 

 where we cannot trace it to an over-supply of food or to 

 enforced idleness on account of vicissitudes of weather, or to 

 both combined. 



Sudden and prolonged exposure of horses to depressing 

 atmospheric influences, as cold and moisture, after smart exer- 

 tion, even when previously in the enjoyment of the fullest 

 amount of health and vigour, will often in certain animals 

 develop an attack of weed by suddenly disturbing or arresting- 

 normal functional activities connected with digestion and food- 

 assimilation. 



Although most frequently encountered and chiefly interest- 

 ing to us as a systemic or constitutional disturbance ter- 

 minating in local structural changes, lymphangitis is some- 

 times seen as simply local inflammation of the absorbent 

 vessels of the limb or other parts of the body, the result of 

 injuries. In the limbs the most fruitful cause of this form of 



