72 Liuiyworiu Disease. 



ber and size of the iiiflainmatory foci stand in direct relation to 

 the anionnt of the worm brood, either disseminated and g-ener- 

 ally small inflammatory foci are developed in the Inngs (broncho- 

 pnenmonia verminosa lolndaris) or the inflammation remains 

 confined solely to the infected bronchns. Dnrini^ their fnrther 

 development, most king-worms (excepting strongylns capillaris 

 and strongylns connnntatus) try to enter the larger bronchi, 

 where they reach sexnal matnrity and also canse an 

 inflammation which, however, is mostly due to the deposited ova 

 or the escaped embryos. Embryos may be aspirated into the 

 smaller l)ranches of the larger bronchns or w^ander there ac- 

 tively and after perforating the wall of the ])ronchioles, get into 

 the Inng parenchyma, where they produce inflammatory changes, 

 and in this nianner inflaimnatory foci develop in large numbers 

 and in considerable extent (bronchopneumonia lobularis dis- 

 seminata). However, the spread of worm pneumonia probably 

 depends partly upon the auxiliary action of bacteria (Joest). 

 In consequence of perforation of the bronchial wall by the em- 

 bryos, air may get from the bronchial lumen into the lung par- 

 enchyma. But it is questionable whether interstitial emphy- 

 sema of the lungs, which is seen frequently in cattle in connec- 

 tion with lungworm disease, is mainly due to perforation of the 

 bronchial wall, as claimed by Joest, since the bronchial lumen is 

 usually obstructed by masses of exudate before perforation 

 occurs. Paroxysms of cough due to the existing bronchial 

 catarrh appear much more important. Sexually mature worms 

 (Str. capillaris and Str. commutatus) invading the lung tissue 

 or embryos (Str. vasorum and Ollulanus tricuspis) by way of 

 the blood current give rise to the formation of miliary or some- 

 what larger inflammatory foci. 



From the bronchi the inflammatory process usually spreads 

 to the peribronchial tissue and even further, and the diminution 

 of elasticity of the bronchial walls induced in this manner, gives 

 rise to^ a dilatation of the larger bronchi. Occasionally some 

 l)ronchi are obstructe<l by masses of worms and secretions, 

 causing atelectasis of the affected portion of the lung, which 

 again forms the basis for a bronchopneumonic focus. If em- 

 bryos are swallowed in great numbers, they may interfere with 

 digestion. 



From the iiivcstigatioiis of Ligniere one may conclude that lung- 

 worm disease furnishes a t'avoralile soil for the development of S(>eondary 

 infections, particularly to the l)ipolar bacilli of liemorrliagic sei)ticeinia. 



Extensive l)roncliial catarrh or bronchopneumonia cause 

 disturbances of nutrition in consequence of an incr(>ased 

 (l('('()mj)()siti()n. 



Anatomical Changes. These are quite varinbk' according 

 to tlic i!inii1)er of lung worms, to single or i-epoalcd i]iv;;s:ons, to 



