41 8 Veterinary Medicine. 



at intervals, and extended through the aortic walls projecting ex- 

 ternally and showing a bloody spot or extravasation on the inner 

 coat. The intima might be abraded or the seat of an exudate or 

 coagulum. The smaller nodules contain the embryos, while in 

 the large the sexually mature worms may be found. Part of the 

 worm may protrude into the vessel among the flowing blood. 

 They are rare in the po,sterior aorta," yet they have been found in 

 the vicinity of the renal arteries by Morgagni and Megnin, re- 

 spectively. The embryos are believed to undergo evolution in 

 the circulating blood, but the full life history of the parasite re- 

 mains unknown. 



Symptoms. Lewis has seen the lumen of the aorta all but 

 blocked by a clot determined by the worm. Manson asserts that 

 the rupture of the cyst may bring on a fatal pleurisy. He fur- 

 ther claims that entering the circulation the embryos cause clots 

 and emboli of the .spinal cord with consequent paraplegia. Again 

 dogs die suddenly from rapidly induced anaemia cau.sed by 

 rupture of the aortic walls which have become softened and 

 atheromatous around the verminous nodules (Megnin, Chauvrat, 

 Perroncito, Caparini). 



Treatment. So long as the life history of the worm is imper- 

 fect prevention and treatment can only be attempted along general 

 lines as advised for filaria immitis. 



Strongylus Vasorum. Already referred to under lung 

 worms of the dog ; this, as its name implies, is essentially a para- 

 site of the blood and blood vessels. The result is endocarditis, 

 and endarteritis, with the formation of clots and embolisms, yet 

 in many cases the presence of the worms has not given rise to 

 appreciable symptoms. (See under Lung worms of Dogs). 



H^MATOZOA OF BIRDS. 



Protozoa : Like pla««aodium malarise in red globules. Birds nearly im- 

 mune from their ill-effects. Trypanosoma sanguinis avium : Shows no 

 pathogenesis on birds. Nematodes : Filaria round heart of duck, others in 

 connective tissue and in blood. 



Protozoa. In the blood of birds in malarial districts have 

 been found protozoa resembling in form and transitions the 

 Plasmodium malariae of man. These have been found as hyaline 



