Cclxxxiii. the Estimation of Vitamin B1 in Blood

MEIKLEJOHN [1937] has described a method, based upon the work of Schopfer [1935], of estimating vitamin B1 in "small samples" (15 ml.) of blood. From his evidence he concludes "that the method... provides a quantitative estimate of the true vitamin B1 content of the blood". Since a clinical test for vitamin B1 in blood is badly needed, and since Meiklejohn's method is being used by several workers in this country and in others, it seemed to be important to examine the justification of his claim and the value of the test. The basis of the method lies in the ability of vitamin B1 to promote the growth of a fungus, Phycomyces blakesleeanus. There is already sufficient evidence contained in Meiklejohn's paper and in Schopfer's numerous publications to show that the former's claim needs investigation. Schopfer & Jung [1937, 2] have published tentative conclusions: "Le sang donne une r6action positive. En exprimant en aneurine la totalit6 de l'action auxog6ne observee, on arriverait A des teneurs variant entre 0-2 et 04y par cm.3 de s6rum." The animal used is not mentioned. In his other paper mentioning determinations on blood, Schopfer [1937] states: "Avec le serum, nous avoils trouv6 une fois 39 mg. de recolte avec 1 ccm. (rat m0le) et une fois 69 mg. pour 1 ccm. (rat femelle); en comparant avec les donn6es fournies par la vitamine pure, nous trouvons que 0-2y de cette derniere livre une recolte de 65 mg." He then warns us of the danger of expressing all growth-promoting activity in terms of vitamin B1, since "nous savons que d'autres facteurs agissent egalement". Although results on two rats hardly merit discussion, it is instructive to examine the only experimental results that he has published (presumably obtained with the male rat): Approx. value for apparent Dry wt. of vitamin B1 (y/100 ml.) Rat serum fungus calculated from Schopfer's vol. in ml. mg. figures 0*5 34 17 1.0 39 10 2.0 47 6-5 Rat red blood 77 15 corpuscles "about 2 ml."