Infective Lymphangitis. Traiiniatic Ly^nphangieis. 393 



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 cr 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 insufficient 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 operat- 

 ing instrument of the surgeon, by his fingers or the dust from his 

 hair or clothes. The wound is perhaps more likely to be infect- 

 ing if it leads to no effusion of blood, but affects only the thick- 

 ness 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 

 speciall}^ 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 some- 

 what 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 the microbes. 



Nearly all microbian diseases make their inroad by way of the 

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

 cytosis as do the numerous moving cells of the blood. Hence a 



