368 Surgical Diseases ^nd Surgery of the Dog 



wounds or the irritation induced by the passage of calculi. Koch 

 refers to stricture of the Vagina, and Siedamgrotzky and Almy have 

 seen stricture of the Ureter. 



(3) Tumors Proper 



The effect of tumors on the organism is variable, but they 

 all have their being at its expense, performing no physiologic 

 function and contributing nothing to its support, and are therefore 

 truly parasitic. 



Malignant growths have for their chief characteristics: inva- 

 sion of all the textures of the part in which they develop, rapidity 

 of growth, profound influence on the general health from the first, 

 tendency to recurrence after apparent extirpation, whioh means 

 a continued growth of left-over particles, and metastasis to other 

 and distant organs through the medium of the circulation or by the 

 lymphatic channels. They commonly ulcerate. On the other hand. 

 Innocent growths are generally well encapsulated, and do not in- 

 filtrate the surrounding structures, they grow slowly and with few 

 exceptions disturb the general health biit little, they do not return 

 if completely removed, and do not produce secondary growths in 

 other parts of the body. While innocent tumors rarely undergo 

 a true process of ulceration, yet they are very frequently rendered 

 raw and sore by constant licking on the part of the animal, or by 

 abrasion through contact with the ground. They are sometimes 

 dangerous by reason of pressure they may exert on vital structures. 

 For instance, simple enlargements of the prostate gland are fre- 

 quently provocative of urinary troubles, and mediastinal neoplasms, 

 whether malignant or innocent, tend to give rise to nervous, cardiac, 

 respiratory, vascular, and digestive troubles. In the anterior me- 

 diastinum are found two groups of lymphatic glands — ^the bron- 

 chial, situated in the angle of bifurcation of the trachea, around 

 the origin of the bronchi, adjacent to which they extend for a 

 short distance into the pulmonary tissue, — and two trains of lo- 

 bules extend along the inferior face of the trachea from the base 

 of the heart to the first rib. Intimately related with these groups 

 are the anterior aorta and vena cava, cardiac, recurrent, and diaph- 

 ragmatic nerves, inferior cervical ganglia of the great sympathetic, 

 base of the heart, and vena azygos. Inflammatory tumors, such 



