i INTEENAL PEOTECTIVE SECEETIONS 25 



tested in our laboratory by the so-called washing of the blood in 

 dethyroidised dogs, i.e. the repeated injection into the veins of an 

 isotonic solution of sodium chloride in quantities large enough to 

 increase the urinary secretion and accelerate the elimination of 

 all the toxic products accumulated in the blood. Our results 

 were approximately identical with those obtained by Fano ; after 

 each injection the morbid symptoms were alleviated or entirely 

 disappeared for some time. 



This temporary cessation of all the symptoms is strictly 

 associated with the increased diuresis, and thus with the normal 

 functions of the kidneys. When the latter are affected and do 

 not expel the excess of injected fluid fast enough, the symptoms of 

 cachexia are not suspended. 



Another important fact appears from the researches of Dutto 

 and Lo Monaco. These authors found on methodical analysis of 

 the urine that elimination of nitrogenous waste products diminishes 

 in dethyroidised dogs, so that they accumulate in the body : the 

 washing of the blood abolishes the symptoms of cachexia thyreo- 

 priva because it determines the elimination by way of the kidneys 

 of these nitrogenous products, which had been retained and 

 accumulated in the body. 



These experimental results as a whole reinforce the hypothesis 

 formulated by ourselves, to the effect that the toxic substances 

 which determine tetany and cachexia thyreopriva are katabolic or 

 waste products from the tissues, i.e., they have the same origin, 

 and, in part at least, consist of the same urinary materials. It 

 appears from certain experiments of Vassale and Eossi (1893) that 

 these toxic substances are largely derived from the muscles, which 

 represent the tissue that predominates considerably over any other 

 in the body. These authors studied the degree of toxicity of the 

 juice prepared from the muscles of normal dogs, compared with 

 that of the muscles of dogs killed when suffering from tetany and 

 cachexia thyreopriva. The muscular extract of healthy dogs 

 yielded negative results : the muscular extract of dogs in tetany, 

 on the contrary, when injected into the veins of dogs that were 

 normal or recently deprived of the thyroid, induced the gravest 

 symptoms, anorexia, vomiting, fibrillar contractions, and event- 

 ually convulsions. 



If (as appears highly probable from what we have been stating) 

 the phenomena of tetany and cachexia thyreopriva really depend 

 on auto-intoxication ; if the toxic substances by which this is 

 determined are the waste products from the various tissues, notably 

 from the muscles which form the predominating tissue ; if these 

 toxic katabolites are normally eliminated by the renal system as 

 fast as they are formed, then the protective, antitoxic action of the 

 thyroid secretion may validly be conceived as the direct or indirect 

 effect of a physiological excitation of the renal epithelia. The 



