INFLUENZA AND THE INFECTIOUS DISEASES OF THE HORSE. 259 
very often followed by disorder of other parts, and therewith 
acts directly as a predisposing and exciting cause. For instance, 
the acute affections of the endocardium pass over to the pericar¬ 
dium, and the reverse. Diseased condition of the serous mem¬ 
branes have likewise changes of the muscles to fleshy parts of the 
heart as a result. Infiltrations and curvatures of the valves of 
the heart produce an enlargement of the cavity, incrassation or 
attenuations of the walls of the heart, etc. 
According to the age of the animal, nothing can be inferred 
with certainty. At all ages heart affections can occur; still, these 
affections, according to my observations, as before mentioned, 
seem to occur more frequently among young animals than among 
older ones. Forage and attendance have great influence upon 
the origin of heart disease ; especially is this true of the nobler 
breeds and stock which are kept in good condition. Fatty de¬ 
generation, new formation of fatty tissue already in the normal 
state, will, while an animal is subjected to great exertion, or in 
the beginning of training, especially if it is forced, give rise to 
disturbances in the heart functions, which, if they continue, 
develop into acute or chronic diseases. 
{To be continued .) 
INFLUENZA AND THE INFECTIOUS DISEASES OF THE HORSE. 
By Peof. Dieokerhoff. 
Though immense progress has undoubtedly been made within 
the last three years in the differential diagnosis of the various 
contagious diseases of the horse, which have been grouped for a 
century past in veterinary medicine under the general designa¬ 
tion of influenza, our knowledge of the specific nature of each is 
still incomplete, and it cannot be perfected until we shall have 
enjoyed the benefit of new and more exact observations. We 
shall probably be obliged to wait very long for the discovery of 
the various micro-organisms by which they are generated, and 
the consequent preparation of successive cultures of the appro¬ 
priate microbes. The inoculation of healthy horses by these will 
then easily determine the varieties of the disease or diseases in 
