ANEURINE (thiamine) 



7. BIOLOGICAL ESTIMATION OF ANEURINE 



Polyneuritic Pigeons 



A few of the methods used in the estimation of vitamin B^ in 

 natural substances have been referred to above when discussing the 

 isolation of the vitamin. The prevention or cure of polyneuritis in 

 ricebirds was used by B. C. P. Jansen and W. F. Donath/ whilst Edie 

 et al.^ H. W. Kinnersley and R. A. Peters,^ and K. H. Coward et al.'^ 

 used polyneuritic pigeons, comparing the amount of test substance 

 required to cure the symptoms in one group of birds with the amount 

 of a standard preparation required to cure those in another group. 

 Alternatively the minimum amount of substance required to maintain 

 the weight of a standard bird on a polished rice diet was sometimes 

 estimated, as in Seidell's method.^ K. H. Coward and B. G. E. 

 Morgan ® found that there was a direct relationship between the dose 

 and the percentage of birds cured, but not between the dose and the 

 duration of cure, thus confirming the earlier work of Kinnersley and 

 Peters. 



CatatorulinTest 



An interesting variant of the pigeon method is the catatorulin test, 

 proposed by Peters et al.,'^ in which the oxygen uptake of avitaminous 

 pigeons' brain was measured before and after the addition of the test 

 solution. 



Chick Method 



A method of estimating aneurine, in which chicks are used, was 

 described by T. H. Jukes and H. Heitman.^ The basal diet consisted 

 of polished rice, fish meal and autoclaved yeast, and the results were 

 evaluated from a curve obtained by plotting the " polyneuritic mor- 

 tality index ", i.e. the length of the test period (twenty-eight days) 

 minus the number of days' survival, against the amounts of aneurine 

 added to the diet. Chicks required 135 to 150 /xg. of aneurine per 

 100 g. of diet to maintain normal health. 



Rat Weight Test 



The pigeon has been supplanted as a test animal by the rat. H. C. 

 Sherman and A. Spohn ^ devised a method that was in general use for 

 some years and is similar in principle to that of Guha and Drummond ^° 

 already referred to. The success of the method depends to a consider- 

 able extent on the selection of the experimental animals. An inbred 

 strain is preferred, many would say is essential, and the groups of 



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