56 Water-Soluble B 
We sought, as suitable material with which to work, a vege- 
table product which, after the removal of fats by ether, gave 
promise of yielding the smallest amount of alcohol-soluble matter, 
The navy bean was selected, but this seed we now feel will not 
prove superior to a number of others which might have been 
employed. The bean is extremely difficult to grind to a fine state 
and after ether has removed everything which it is capable of 
extracting, alcohol still extracts about 4 per cent of the original 
weight of the bean. The bean is, however, very rich in the diet- 
ary B (5), and, as will be shown later, there seems good reason 
to expect that a method can be developed for separating the 
desired substance in a greatly concentrated form. 
The navy beans were ground and dried, then exhausted with 
ether. ‘This solvent does not take up a demonstrable amount of 
the water-soluble B. The ether-extracted material was subse- 
quently extracted as described in the experimental part of this 
paper. Wheat embryo similarly treated was employed in some | 
of the experiments. 
We believe our method which consists of testing preparations 
for the presence of the antineuritic substance, water-soluble B, 
by relieving the polyneuritic condition and inducing subsequent 
growth in a mammal, to be greatly superior to the conventional 
method of ‘curing’? pigeons which have been fed an exclusive 
diet of polished rice until they develop the disease. Polished rice 
is very deficient from the dietary standpoint in certain mineral 
salts, the fat-soluble A, and protein. in addition to the specific 
substance water-soluble B, the lack of which leads to the devel- 
opment of polyneuritis (6). Recovery cannot be permanent on 
such a diet, and the observation of the ‘‘curative”’ effects of the 
administered substances is necessarily limited to a brief period. 
We decided to adopt the rat instead of the pigeon as an ex- 
perimental animal, because of the fact that the element of growth 
can be included in the observations. Where growth takes place 
and is sustained, there can be no possible doubt that we are sup- 
plying a chemical complex which is necessary as a food rather 
than a complex which produces its effects through pharmaco- — 
logical action. In the work with pigeons, previously reported 
(4), we had ample experience to convince us of the prompt re- 
covery of birds from the polyneuritic state when given various 
