The principal results are summarized as follows:
(1) General constituent of sotetsu pollen was determined; in the result it did not contained a starch.
(2) In sotetsu pollen, the formaldehyde-containing substance was not contained.
(3) The adenine and choline, in free state, were isolated from sotetsu pollen.
(4) An attempt at the isolations of spermine and protamine from sotetsu pollen was ended in negative results.
The writer wishes to express his thanks to Dr. K. Yoshimura and Prof. Dr. Y. Okuda for their having interest on the problem, and also begs to acknowledge with thanks that a part of the expense of this study was defrayed from a grant given by the Nippon Gakuzyutsu-shinkokwai.

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In a previous paper⁽¹⁾ K. Kawakami and the present author⁽²⁾ have reported that they have prepared crystalline compounds of fatty acid or benzoic esters of vitamin A by condensing them with maleic anhydride, but these crystals had no physiological activity and could not be regenerated into vitamin A.
The present author has now succeeded in preparing a crystalline ester of vitamin A by treating vitamin A concentrate (Biosterin) with β-naphthoyl chloride in presence of pyridine and proved to have the activity of 7200 C. L. O. units after Carr-Price test. It readily promotes the growth of albino rats and cures, the; xerophthalmia. Dr. S. Kato in our institute has observed that a 1/140, 000 mol methyl alcoholic solution of the crystals show absorption bands at 3595, 3385, 3060, 2920, 2816 Å besides the maximum at 3225 Å.
The crystals have the formula C₃₁H₃₆O₂, mp 76°, it is easily hydrolysed by alcoholic potash into β-naphthoic acid, C₁₁H₈O₂, and pure vitamin A, the analysis of which agrees with the formula proposed by P. Karrer, i. e., C₂₀H₃₀O. Thus it has been definitely proved that the crystals are the ester of β-naphthoic acid and vitamin A.

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