Patliogeiiesis. Anatomical Changes. Syinjitoms. 257 



species of ranunculus, colcliicuni autumnale, tol)acc(), mould) 

 wliicli produce a paralyzing effect through their |)oisons upon 

 the niuscularis of the rumen. This form of bloatino- does not 

 usually attain a very high degree. Obstruction of the esoph- 

 agus causes severe meteorism, particularly if the food pre- 

 viously ingested is fermentable. 



Pathogenesis. In consequence of the rapid formation of 

 gas the rumen l)ecomes dilated in a short time, and the disturb- 

 ances are similar to those caused by overfilling of the rumen 

 combined with meteorism (see page 250), but with this differ- 

 ence that bloating occurs much more rapidly and the symptoms 

 are more fulminant, occasionally even leading to rupture of the 



Anatomical Changes. A considerable increase of the abdo- 

 men and of the rumen becomes at once manifest. The wall of 

 the rumen is so tense that it can hardly be pressed in at all with 

 the hand. Sometimes, one may be able to recognize during life 

 a rupture of the rumen or of the diaphragm. On post-mortem 

 the lungs are compressed by the diaphragm bulging into the 

 thorax; they are dark red and full of blood. The vessels out- 

 side of the abdomen, especially the veins and particularly those 

 of the subcutaneous connective tissue, are filled to their utmost 

 with black red, possibly uncoagulated, lilood. The signs of 

 death from suffocation also include punctate and striate hem- 

 orrhages into the serous membranes, especially into the pleura 

 and pericardium. 



On post-mortem examination the rumen is found to contain 

 soft, mashy, fermenting food masses and large amounts of gases 

 which are inflammable and burn with a blue flame. 



The composition of the gaseous contents of the rumen varies according to 

 the type of food and to the nature of the fermentative process. Carbonic acid 

 is always present to a large extent (50 to SO'/r) ; the amount is the larger the 

 more fermentable the feed has been and the larger were the morsels upon ingestion. 

 Next conies methan gas (CH,) which makes up 16 to 39% of the gases. There 

 are also present sulphuretted hydrogen, nitrogen and oxygen, the latter two derived 

 from the air which has been swallowed. Oxygen, however, may be used up com- 

 pletely during the fermentative process. In starving animals the amount of carbonic 

 acid becomes smaller, while methan, nitrogen and oxygen are increased (Lungwitz). 



S3miptoms. The animals cease to feed, stand motion- 

 less, place their feet under the abdomen or spread them, curve 

 their back, turn their head around towards the abdomen, and 

 stop ruminating. 



A short time later an increase in the circumference of the 

 abdomen becomes noticeable ; it soon reaches a high degree. The 

 increase takes place all around the abdomen, becoming, how- 

 ever, most marked on the left side, particularly before death. 

 The flanks, especially the left one, iDecome flattened; in severe 

 cases the left flank may so protrude that its apex is higher than 



