Antineuritic yeast concentrates. III

Abstract

STANDARDISATION OF THE TEST. CURATIVE tests upon the pigeon have two main advantages over other methods of testing for the antineuritic principle. Firstly, it is not yet absolutely certain that rat tests can differentiate the curative factor in the vitamin B complex. This matter has been discussed elsewhere [Kinnersley and Peters, 1927], so that it is not necessary to reiterate the evidence here. Secondly, the pigeon is an easy bird to obtain, and to manage, and further it gives a rapid answer with small amounts of test material. It has been the object of the tests carried out in this Department during the last four years to discover the errors to which the test is liable and to learn how to avoid them. An account of the position of the pigeon test is needed at the present time, owing to the appearance of statements in the recent literature tending to discredit the use of the pigeon for short curative experiments. Jansen and Donath [1927] for instance discarded the pigeon as a test object owing to confirmation of Theiler's experiment, in which it was found that birds could be occasionally cured by injections of distilled water. In a recent paper by Plimmer, Rosedale, Raymond and Lowndes [1927] the authors have used both curative and preventive tests. They have found that the results ob- tained with the curative test depend upon the state of the bird, and that, though there is general agreement between the preventive and curative tests, occasionally there are wide divergences. These discrepancies may be due to some in:herent error in the curative tests; they may however be ascribed to the fact that preventive tests carried out over prolonged periods such as 60-100 days test for more than one factor. This latter explanation would seem to be the conclusion to be drawn from the results recorded in this communication.