150 POULTRY DISEASES 



as in other portions of the abdomen, especially in the mesen- 

 tery and in the abdominal walls. 



In these cases, on autopsy, the liver will be found to be 

 enlarged, brownish or greyish-brown in color (mottled), fri- 

 able (tears easily), and when cut through appears "greasy," 

 nnich fat adhering to the knife blade. In these cases rupture 

 of the liver often occurs when the hen is stepped upon hy a 

 large animal, is thrown or jumps a long distance on hard 

 ground or a concrete floor. Heavy hens with clipped wmgs 

 are prone to this injury. 



In the liver, in which excessive fat is stored up, there is, 

 after a while, an encroachment upon the protoplasm to such 

 an extent that the cells cannot properly functionate and 

 then death of the bird may occur. In these cases a micro- 

 scopic examination shows the nuclei of the cells to be pushed 

 to one side, and the protoplasm atrophied and disappearing. 

 This is a pathological condition. 



RUPTURE OF THE LIVER 



In cases where the liver is excessively congested with liiood 

 or is overly filled with fat, as mentioned above, violence may 

 result in rupture. 



One case that may be of interest came to the laboratory, and at 

 autopsy was found to be ruptured, with considerable blood (hemor- 

 rhage) in the abdominal cavity (among the intestines). The rup- 

 ture or tear was about three-quarters of an inch long and on the 

 left lobe. The organ was double its normal size. Upon microscopic 

 examination it was found to be congested and occasional small rup- 

 tures (hemorrhages) were found throughout the liver substance. 



This bird was in a yard with a horse and it is supposed to have 

 been kicked or stepped upon, as the left side was bruised. 



CONGESTION OF THE LIVER 



There are two kinds of congestion of the liver, active and 

 passive. Active congestion precedes infiannnation and is a 

 state in which the capillaries, arterioles and arteries are en- 

 gorged with blood. It is caused by local irritation. 



Pa.ssive congestion of the liver is usually due to a weak 

 heart or a leaky valve between the two cavities of the right 

 side. The blood backs up into the liver, and the central 

 veins of the lobules and capillaries, between the columns of 

 liver cells, become engorged. It gives the cut surface a ])ecu- 

 liar yellowish mottled api)ea ranee called ''nutmeg liver," 

 from a fancied resemblance that it bears to the sectional sur- 

 face of a nutmeg. 



