Pathogenesis. Anatomical Changes. 163 



the animal lias been reduced to such an extent that other bac- 

 teria, especially the Preisz-Nocard bacillus of pseudo-tubercu- 

 losis (see that disease), may attack the tissues of the body and 

 produce an inflammation of the lung tissue. 



In these cases which have become chronic, catarrhal pneumonia 

 leading to caseation and suppuration can usually be discovered. 

 Bacilli of pseudo-tuberculosis may be demonstrated in the affected 

 tissues in association with other bacteria (pus cocci, bacillus necrophorus, 

 streptothrix, colon and paracolon bacilli). Their occasional pathogenic 

 action has been proven by Nocard by the following experiment : A 

 calf three weeks old was injected intra-peritoneally with 100 cc. of 

 culture of the bipolar bacillus, which had previously been heated for 

 one hour to 60° C, and after six hours it was made to inhale a bouillon 

 culture of the bacillus of pseudo-tuberculosis for five minutes. The 

 autopsy which was performed eight days later, revealed numerous 

 catarrhal-pneumonic areas in the lungs. In a second calf, which was 

 not given the injection of the killed culture of the bipolar bacilli, the 

 inhalation of the pseudo-tubercle bacilli caused no changes in the lungs. 



According to Moussu broncho-pneumonia may develop in sucking 

 calves also, from the aspiration of the amniotic fluid into the air passages 

 during difficult births. The infection occurs in these cases while the 

 head is lodged in the vagina, and with the commencing respiratory 

 movements the aspiration of the fluid takes place. 



Anatomical Changes. In some of the acute cases the um- 

 bilicus is swollen and dense. The borders of the umbilical 

 opening of the ring which has not closed are infiltrated; some- 

 times they are ulcerated, and a purulent ichorous secretion may 

 be pressed out of the same. An incision frequently reveals an 

 abscess lying in the abdominal wall. 



The umbilical vein in colts, also one or both umbilical 

 arteries (Gmelin), are greatly thickened and of a firm or fluctu- 

 ating consistence in their entire length, or only in parts. In 

 different places the lumen is filled with blood coagulum, w^hich 

 in various parts or along its entire length appears of a dirty 

 red color, and sometimes liquefied to a thick fetid mass. The 

 surface of the intima is covered with fibrinous shreds or with 

 puriform softened masses under wdiich there may be ulcerations. 

 The other layers of the wall of the vessel, as w^ell as the sur- 

 rounding connective tissue, are sometimes only infiltrated with 

 the serous fluid, in other cases again with fibrinous purulent 

 exudate. In case the inflammation has extended to the adjacent 

 peritoneum the abdominal organs lying close to the affected 

 areas usually show^ adhesions by fibrinous pseudo-membranes 

 (intestines, omentum, liver, in colts also the bladder). All these 

 changes may be present without an affection of the umbilicus. 

 In the branches of the portal vein, inside of the liver tissue, 

 similar thrombi may occur, wdiile on the other hand, the throm- 

 bus of the vein may occasionally extend into the ductus Arantii, 

 and may even penetrate with its blunt end into the lumen of 

 the vena cava. The thrombi of the umbilical arteries may reach 



