154 Veterinary Medicine. 



in man and associated with dyspepsia and gastric dilation, 

 Bouveret and Devic have extracted from the contents of the 

 stomach a toxic substance which caused tetanic convulsions in 

 animals. The total removal of the thyroid gland, or even of 

 four-fifths of it (Eiselsberg) , in the cat is found to be invariably 

 followed by tetany. 



Causes. Beside the origin from the removal or general disease 

 or degeneration of the thyroid, it has been attributed to dige.stive 

 troubles, associated with fermentations and the production of 

 toxic matters, to rheumatism, infection and malaria, to rachitis 

 and unhygienic conditions. The systematic changes and trials of 

 growth and development, of pregnancy and lactation, seem to be 

 factors in certain cases. A peculiar irritable nervous organiza- 

 tion transmitted by heredity is undoubtedly a potent cause, and 

 upon this, bacteridian, leucocytic and other poisons operate so as 

 to rouse the paroxysms. 



Symptoms. There are usually prodromata in the shape of dull- 

 ness, prostration, weariness, and some dullness of the special 

 senses. Fever is commonly absent and the contractions tend to 

 affect both flexors and extensors, but as the force of the first 

 predominates, the affected member is usually held more or less 

 rigidly semi-flexed. The spasm appears suddenly, often taking 

 occasion of some voluntary movement, and may last for several 

 minutes or hours. It is followed by an interval of relaxation of 

 equally uncertain duration. Though usually attacking the limbs 

 and causing the victim to walk on the toes, it may extend to the 

 face, neck or trunk, and constitute an intermittent trismus, 

 oposthotonos or emprosthotonos. 



Diagnosis. Tetany is to be distinguished from tetanus by the 

 complete intermissions of the spasms, and by the voluntary de- 

 velopment of these by compression of the presiding nerve or 

 artery. Pressure on the nerve arouses its excitability, and com- 

 pression of the artery shutting off the supply of blood from the 

 disordered and susceptible muscles, tends to increase their irrita- 

 bility. I^igature of an artery supplying healthy muscles causes 

 simple trembling of such organs. From the spasms of cerebral 

 spinal or meningeal inflammation tetany is distinguished by the 

 absence of fever, and the complete intermissions of the paroxysms. 

 The spasms of ergotism bear the closest relation to those of tetany 



