402 THE BIOCHEMISTRY OF B VITAMINS 



Wernicke's disease is marked by rather different symptoms, largely of 

 a cerebral nature. 37 A typical hemorrhagic lesion of the third and fourth 

 ventricles of the brain frequently associated with polyneuritis and 

 alcoholism (and found in thiamine-deficient pigeons) is the principal 

 anatomical sign, while symptoms involve lethargy and excitability, coma, 

 nystagmus (a rapid involuntary oscillation of the eyeball) , vomiting, and 

 cardiac and respiratory irregularities. The reasons for the manifestation 

 of thiamine deficiency in different individuals in such a variety of ways 

 are unknown. It has been variously proposed that the critical factor is a 

 matter of degree of deficiency, of compound deficiencies or pathologies, or 

 of varying sensitivities of the several affected systems in different indi- 

 viduals. A large number of other animal species have been rendered 

 thiamine-deficient and their symptomatology studied; to a large extent, 

 the principal symptoms are those found in beriberi. 



In the complete absence of thiamine mice die so rapidly that typical 

 symptoms do not develop; but in a more gradual depletion they cease to 

 grow, lose weight, undergo convulsions (especially when spun by the tail), 

 and exhibit brain and muscular lesions and testicular degeneration. 44 



Rats follow a similar course, exhibiting a failure to grow and a loss of 

 weight, followed by typical convulsions and polyneuritis. Assay methods 

 exist for thiamine which depend on either growth, 45 or the prevention or 

 cure of polyneuritis in rats. 46 The normal heart rate of rats is from 500 to 

 530 beats per minute, and on a thiamine-free diet this drops to 250 to 300 

 per minute after about two weeks. The remission of this bradycardia has 

 also found considerable use as a thiamine assay technique, because of its 

 rapidity, economy of animals, and relative ease and accuracy. 47 



Thiamine deficiency in the fox, ferret, and mink is generally referred 

 to as Chastek paralysis (p. 292) . In young foxes, death occurs before 

 other typical symptoms occur; but in older ones, a period of anorexia is 

 followed by general weakness, ataxia (lack of ability to coordinate 

 muscular movements), and spastic paralysis. The paralysis is character- 

 ized by extreme board-like stiffness with the heads drawn back, but by 

 no signs of mental effects. Death may occur before the paralysis is com- 

 plete, or may not ensue until the complete paralysis has been developed 

 for some time. Autopsy reveals cardiac edema and degeneration, and 

 hepatic congestion, hemorrhage, and necrosis. Typical Wernicke lesions 

 are found in the brain of foxes after about 40 days' depletion, whereas 

 they occur in dogs only after prolonged chronic deficiency. 



Thiamine deficiency has been studied in a wide variety of other animals, 

 important among which are cats, 48 monkeys, 49 cattle, 50 and birds. Eijkman 

 and Grijn's original observations on thiamine deficiency and the curative 

 effects of rice polishings were made on chickens. Pigeons were extensively 



