( 905 ) 
before Oet. 1910 1 could accomplish this design, when Prof. SPRONCK 
was kind enough to place at my disposal a room provided with 
all that was indispensable for such an investigation, to be used as a 
laboratory. I set high value on the fact that I may add to this that 
Prof. Spronck is quite willing to declare that the nature and course 
of my investigations remained entirely unknown to him. 
In order to examine chickens suffering from Polyneuritis gallina- 
rum had first to make healthy chickens ill, and succeeded in doing 
so, according to the method taught by Ekman i.e. by compulsory 
feeding with white entirely prepared rice.') After 18 or 19 days 
every chicken thus fed became ill, showing the wellknown symp- 
toms of Poiyneuritis gallinarum. ®) 
During these experiments [ observed in the first place that during 
November and the first half of December the rice, neutral after 
sterilization,’) grew sour within a few hours when it was exposed 
to the air. The tirst thing | wanted to know now was: Why does 
rice acetify?*) Nobody could give an answer to this question, 
not even Prof. Bryrrinck of Delft, who kindly listened to my 
questions but felt even inclined to doubt the fact; I myself could 
however doubt no longer, for I saw that rice kept, after the steriliz- 
ation, in well shut vessels remained neutral, whilst L saw it turn 
sour when it was exposed to the air in the different rooms of this new 
laboratory, where never before experiments concerning fermentation 
had been made. The rice turned also sour in the crop and in the 
intestines of chickens. From the above it appears that the rice did 
not turn sour by a simple chemical process. Consequently the rice 
must turn sour either by bacteria of the intestines or by bacteria 
of the air, or by both. By a series of experiments the obligate bacteria 
of the intestines of chickens were soon excluded, consequently had 
the acetification to be explained by the bacteria of the air. Now | 
made my investigations in that direction, but it was anything but easy to 
1) In order to exclude however any idea of spoiled rice, the rice was sterilized 
at 120° before it was used. By so doing | obtained likewise a greater conformity 
with the often sterilized articles of food on board sailing-vessels that are so often 
accused of being operators of Beri-beri 
2) Frequent thin defecation, emaciation, paralysis, cyanose, dyspnoe (KIJKMAN). 
3) Uncooked not sterilized rice has always a feebly acid reaction. 
4) As sour fermentation was then for me only a sound to which | could not 
attach any idea, [ applied in the first place to the vinegar-works “de Roos” at 
Amsterdam, where Mr. O. Wixrorru in the kindest way furnished me with inform- 
ation and placed at my disposal the literature about vinegar fabrication; Mr. 
H. VLAANDEREN, a well known dealer in groats here, informed me about the diffe- 
rent sorts of rice, the way of preserving rice etc. etc. To both my sincerest thanks. 
59 
