270 CLINICAL VKTERINARV MEDICINE AND SURCERY. 



of sugar per thousand ; in certain diabetic patients the proportion rises 

 to 5 or 6 per thousand. But an animal whose urine contains sugar is 

 not necessarily a diabetic subject. The temporary presence of sugar in 

 the urine — transitory glycosuria — is, in fact, a symptom common to 

 various morbid states, to certain brain diseases, to auto-intoxications 

 and infections. What particularly characterises diabetes is the 

 constancy or permanency of the condition. Temporary glycosuria or 

 diabetes can be experimentally produced by injuring the floor of the 

 fourth ventricle below the origin of the pneumogastrics, by adminis- 

 tration of various chemical substances, and by extirpation of the 

 pancreas. 



I shall not trouble you with the theories of diabetes. At the present 

 time they number almost thirty. The majority are based on supposed 

 disturbance in the glycogenic function of the liver, or on failure of 

 the tissues to destroy the sugar present in the blood, due to disturbance 

 in assimilation. M. Bouchard regards diabetes as a disease due to 

 retarded nutrition. It results from nutritive disturbance primarily 

 characterised by failure or partial inability of tissue elements to consume 

 the sugar. MM. Chauveau and Kaufmann consider that variations in 

 the proportion of sugar contained in the blood depend rather on hepatic 

 production than on disturbance in consumption, and that production of 

 sugar by the liver is regulated by the nervous system, the pancreas 

 exercising a kind of retarding function and moderating the activity of 

 the hepatic cells. 



According to the rapidity of its development diabetes is described 

 either as acute or chronic. Other "forms have been distinguished, 

 depending on whether the patients preserve their condition or undergo 

 wasting. Some authors refer wasting diabetes to lesions of the 

 pancreas, but in the dog it appears only to be an advanced stage of the 

 hrst form ; wasting, in fact, is always very marked, though lesions of 

 the pancreas are rare. We also recognise traumatic diabetes, most 

 frequently a result of injury to the cranium. 



The progress of diabetes mellitus in the dog is usually rapid. Some 

 patients may live for several months ; under appropriate treatment the 

 glycosuria diminishes, but improvement is only temporary. Sooner or 

 later the symptoms become suddenly aggravated, and most animals die 

 in a state of coma. 



Diabetes in the dog is very apt to escape diagnosis. It may be 

 suspected from the history, from one or other of the principal sym- 

 ptoms, such as the excessive urination, thirst, and appetite; and in 

 certain cases also from the clinical signs — wasting, cataract formation, 



