141 



of the pulmonary veins as described by Sussdorf have not been observed 

 in my material. 



Although the changes due to lung-sickness are not restricted to the 

 puhxLonary tissue, yet the lesions in the lungs are of sufficient value to be 

 of great help in diagnosing pleuro-pneumonia macroscopically. 



1. The interstitia, i.e. the interalveolar, the interlobular, and peri- 

 bronchial connective tissues are the seat of a primary inflammation of 

 serofibrinous character. The chief changes due to inflammation take 

 place in the connective tissue, therefore pleuro-pneumonia can rightly 

 be said to be an interstitial fneumonia. 



2. The disease follows the course of the lymphatic vessels very 

 closely and affect the lymphatic vessels in the first place ; having recourse 

 to the microscopic examination, we must diagnose a lymphangitis 

 serofibrinosa. 



3. The thickening of the septa (which can reach 8 cm.), and the 

 so-called marbling of sections have certainly some diagnostic value, pro- 

 vided that the histological details are in agreement. 



One will never find the described stratified arrangement of cavities 

 and fissures in traumatic pneumonia, so common in cattle in consequence 

 of perforation by foreign bodies ; quite independently of the total differ- 

 ence in histological details. 



4. After sequestration has taken place diagnosis is no longer possible 

 except by microscopical investigation. 



Microscopical Lesions in the Lungs. 



The specimens which were preserved as abeady mentioned in 

 formaline or Orth's liquid, were examined in paraffine or celloidin sections, 

 after staining with haemalum-orange. Van Gieson, May-Grunwald Fischer, 

 Heidenhains-haematoxyline, fibrine staining after Weigert and Kockel* 

 or after Fraenkelf with Best's carmine for glycogen elastic fibrillae after 

 Fraenkel and Mallory. Fjach section was carefully analysed in order to 

 facilitate comprehension and to be able to make comparisons. 



In looking through many specimens, one finds great diversity in 

 details according to whether the sections were taken from pieces of recently 

 diseased lobuh, or from such of more or less chronic cases. However 

 they all have in common that they are stages of a croupous pneumonia, 

 and show conditions that are known already and which have been 

 described elsewhere. It will be readily understood that the specificity 

 of the histological lesions of pleuro-pneumonia will not be found here, 

 although an observer, who has much to do with such specimens might 

 find out details which could help towards a diagnosis. It was shown in 

 the microscopical anatomy of pleuro-pneumonia that all three stages of 



* Ceutralbl f. All. Patholog., Bd. 10. 



tMuench. Mediz. Wochensohriiit No. 50, 1908, \>. 2G3i. 



