562 ABXOKMALITIES IX METABOLISM 



composition, as a side product which is normally protected against 

 by a formation of an antitoxin, rather than bj^ being split up further^ 

 as is the case with the rest of the protein molecule. It is excreted not 

 only in the urine, but also in the breath, and may be produced in vitro 

 by disintegrating protein at temperatures under 40°. Various poisons, 

 cause kenotoxin to appear in the urine, and it is found in the urine 

 of many animals, as well as in plant tissues.**^ The study of anaphy- 

 laxis has led to so many evidences of the remarkable toxicity of the 

 products of protein cleavage, that the possibility that some of these 

 may be responsible for fatigue, as Weichardt has so vigorously main- 

 tained, is receiving much support."* Whether this work is coiitirmed 

 or not, there remains the fact that the blood of fatigued animals 

 contains toxic substances, which ^losso proved as follows: Tf blood 

 is transfused from an exhausted dog to a normal dog, from which 

 an equivalent amount of blood has been withdrawn, this second dog^ 

 will show the usual manifestations of fatigue. 



Mental Fatigue. — The chemical changes of mental fatigue are not 

 known, but it is known that the ganglion-cells show marked struc- 

 tural alterations as a result of fatigue, chromatolysis often being 

 very striking. Since lecithin forms so important a part of the nerv- 

 ous system, it is tempting to imagine that in fatigue excessive quan- 

 tities of its toxic decomposition-product, choline, and the still more 

 toxic derivative of choline, neurine, are formed in considerable 

 amounts and cause part, at least, of the intoxication. 



That choline or neurine actually are the cause of any of the symp- 

 toms of fatigue, however, has not been established ; but Donath '^^ 

 considers choline an important factor in the production of epileptic 

 convulsions J^*^ Animals kept for a long time from sleeping show the 

 presence in their blood, cerebro-spinal fluid and brain tissues, of a 

 poisonous property causing somnolence in other animals (Legendre 

 and Pieron).**' This cannot well be choline or any similar substance, 

 for it does not filter, is insoluble in alcohol, and is destroyed by 

 heating at 65°. 



THE POISONS PRODUCED IN SUPERFICIAL BURNS «* 



In a certain proportion of cases of extensive but superficial burns,, 

 death follows after an interval of from six hours to a few- days, ap- 



03 Cent. f. Bakt.. in07 (4.3), .312. 



•■'♦ The failure of various investigators to corroborate Woiiliardt is disciissod 

 l)v Konricli. Zcit. f. TTvp., 1014 (7S). 1: Korflf-Petersen. ihUJ.. p. 37. 

 ■ o^' Zeit. pliysiol. Chem.. 1003 (.''0), -,20. 



•"■• Confeiiiin<r tlie theories i 'vl I'crature of tlie subjeet of epilepsy in relation 

 to its patliolofjical eliemistry aiu' to aiitoiiitoxieatioii. s(H> the review of ^lasoin. 

 Aroh. internat. de Pharniaeodvnainie, 1004 (13), 3S7. 



«7 Zeit. alljr. Physiol., 1012' (14). 235. 



«s Literature piven li\- P.ardeen. .Tolins Hopkins llosp. Peports. ISOS (7). 137; 

 Eyff, Cent. Orenzf^'el). :\lc(l. u. Cliir.. 1001 i4), 42S: PfeillVr, Virdiow's Areh... 



