Physiology. — “Concerning the Sensitivity to Poisons in Animals 
suffering from Avitaminosis.” By W. Storm van LEEUWEN and 
EF. Verzar. (Communicated by Prof. R. Magnus). 
‘(Communicated at the meeting of November 27, 1920). 
E1ikmMan found in 1893 that fowls, fed on polished rice, develop 
polyneuritis, and that this disease could be prevented by an under- 
milled rice-diet, or by adding to the -polished rice the “silverlayers” 
detached from it. He found, moreover, that in man an abundant 
diet of polished rice subserved the development of beri-beri, whereas 
the disease was not produced, or if already produced, was cured 
when the silverlayers had been added to the rice. Later on it 
appeared that these findings bear on a special case of a general rule. 
Not merely in unhusked rice, but also in all sorts of foodstuffs, 
constituents occur that are essential for the normal growth and the 
healthy condition of men and animals, even though these foodstuffs 
contain an adequate amount of the- proper, long known nutritious 
element. These constituents, whose real nature is unknown as yet, 
are often classed together as “vitamins”. 
Through the latest achievements in this field, notably of American 
workers, our knowledge of these things has largely increased. We 
now know that the term “vitamin” is not applied to a single sub- 
stance, but that it includes various accessory foodstuffs, the fat 
soluble A and the water soluble B, and perhaps a third substance 
C’; we are also aware that according as various nutritious elements 
are wanting in the foodstuffs, the symptoms of a disease may be 
widely different and that these symptoms may also be very different 
in different animals. Many experimental data concerning the occur- 
rence of vitamins in various foodstuffs have been brought forward. 
There is one thing, however, of which we must still admit great 
ignorance, viz. the causation of the symptoms of the disease, reveal- 
ing themselves in animals that suffer from a deficiency of vitamins. 
Some hold that under certain conditions this deficiency brings about 
a predi8position to infection with certain bacteria, but this supposi- 
tion does not afford complete satisfaction and certainly does not 
clarify every case. 
The symptoms of avitaminosis that present themselves are disorders 
