DISEASES OF THE LIVER. 723 



the lungs, by arresting tlie circulation of the bloorl, causes con- 

 gestion of the liver and enteric veins, ana is one cause of the 

 diarrhoea which is so often an accompaniment. 



The second form of congestion is that termed " active," in 

 which the arterial capillaries are mostly involved. This form is 

 induced by food of a stimulating nature, given over-abundantly, 

 particularly during hot weather, or when the animal is not 

 receiving suSicient exercise. It has been already pointed out 

 that animals rapidly got up for sale frequently suffer from a 

 diseased condition of the liver. Dr. William Budd points out 

 how congestions of the liver occur so commonly in the human 

 being ; the sanie reasons are applicable to some extent to the 

 lower animals, particularly as hepatic congestions are generally 

 met with in over-fed, slowly worked, pampered horses, such as 

 those belonging to brewers, or people whose business requires 

 animals for show as well as for labour. He says — " Amid the 

 continual excesses at table of persons in the upper and middle 

 classes of society, an immense variety of noxious matters find 

 their way into the portal blood that should never be present in 

 it, and the mischief which this is calculated to produce is en- 

 hanced by indolent or sedentary habits. The consequence often 

 is that the liver becomes habitually gorged. The same or even 

 worse effects result in the lower classes of our larger towns from 

 the inordinate consumption of gin and porter." Compared to 

 its frequency in man, active congestion in the lower animals is 

 exceedingly rare. The late Professor Colen^an was of opinion 

 that this rarity was due to the simplicity of the liver in the 

 horse — having no gall bladder — compared to its complicated 

 structure in man. This view is evidently erroneous, as the 

 livers of other domesticated animals are furnished with gall 

 bladders, and it cannot be said that they are more liable than 

 the horse to hepatic congestions, except from errors in feeding, 

 to which they are perhaps more frequently exposed. Hutrel 

 d'Arboval takes another view, and describes the exemption from 

 disease to be due to the little areolar tissue entering into the 

 composition of the horse's liver; this view is evidently as 

 erroneous as that of Coleman. 



Symptoms. — In hepatic congestions, as proved by post mortem 

 examinations of animals which have died from " rctmollissemcnt" 

 or softening, with perhaps rupture of both liver and its capsule, 



