546 Veterinary Medicine. 



excessive heat or cold or the presence of chemical irritants and 

 coagulants. These cases are, however, rarely serious and the ten- 

 dency to-day is to trace nearly all cases to infection, from germs 

 already present in the lymph or blood, or introduced through a 

 wound or sore. The effect of germs already circulating was 

 shown in the beautiful demonstrations of Chauveau in regard to 

 calves subjected to castration by subcutaneous torsion (bistourn- 

 age). In the healthy calf the simple operation gave rise to little 

 disturbance. The healthy calf injected with septic liquids equally 

 escaped visible trouble. But the calf injected with septic liquids 

 and then subjected to bistournage had a fatal infecting inflamma- 

 tion. There is a strong presumption that, in lymphangitis, start- 

 ing from an injury with no external sore, the germs were already 

 present in the blood or tissues but were unable to do any serious 

 damage until the injured and weakened part or organ offered an 

 area of lessened resistance to their colonization. Following the 

 same line of thought it has been noticed that animals of a coarse 

 texture, and lymphatic constitution (heavy draft horses and ani- 

 mals raised for the butcher), and such as are debilitated by 

 anaemia, overwork, or poor and insufi&cient nourishment are 

 above all liable to be attacked by lymphangitis. 



The insertion of the septic poison may take place through the 

 bites of insects, the claws or teeth of carnivora that have been 

 devouring tainted or infecting meat, through the lancet or op- 

 erating instrument of the surgeon, by his fingers or the dust 

 from his hair or clothes. The wound is perhaps more likely to 

 be infecting if it leads to no effusion of blood, but affects only 

 the thickness of the epidermis, as there is less chance for the 

 washing out of germs by the flowing blood, and there is less 

 care to employ antiseptics. Wounds in the feet and lower parts 

 of the limbs are specially liable to. infection by reason of their 

 frequent contact with manure and decomposing organic matter 

 in the soil. 



A fresh wound, in which the lymph spaces are exposed, is 

 somewhat more open to infection than one that has advanced to 

 the stage of granulation, the layer of unorganized lymph and 

 cells acting as a slight barrier to the passage of microbes. 



Nearly all microbian diseases make their inroad by way of the 

 lymphatics, where the sparse cells fail to establish as active pha- 



