420 VEDDER. 



of an electric fan, and the residue diluted with distilled water 

 to the original bulk of the extract. 



Four fowls were fed on polished rice plus a daily addition of 

 10 cubic centimeters of the ethereal extract. 



Three fowls developed neuritis in twenty-three, twenty-nine, 

 and thirty-six days respectively. 



Four fowls were fed on polished rice plus a daily addition of 

 10 cubic centimeters of the chloroform extract. One fowl died 

 in thirteen days as the result of an injury received, and 2 fowls 

 developed neuritis on the twenty-eighth and thirty-ninth day 

 respectively. 



The extract of rice polishings remaining after extraction with 

 ether and chloroform was given to 4 fowls fed on polished rice, 

 and these 4 fowls remained well for fifty days when this control 

 experiment was discontinued. It is plain that the neuritis-pre- 

 venting substance still remained in this extract and was, there- 

 fore, insoluble in ether whether acid or alkaline in reaction and 

 was also insoluble in chloroform. It is, therefore, probable 

 that the neuritis-preventing substance is not an alkaloid. 



Iodine is present in small amounts in the human body. Thus 

 it is an important constituent of the thyroid secretion and is 

 also found in smaller amounts in milk. The presence of iodine 

 in the thyroid extract indicates that this element is of the great- 

 est physiologic importance to the organism, but we are entirely 

 ignorant of its mode of action and the reason for its importance. 

 Therefore, it was considered desirable to determine whether 

 polyneuritis gallinarum is caused by the deficiency of this 

 element. 



Experiment 26. — (a) Four fowls were fed on polished rice 

 and given an additional daily dose of 10 cubic centimeters of a 

 solution prepared by dissolving 10 grams of potassium iodide 

 in 1 liter of distilled water. 



All 4 fowls developed neuritis in twenty* twenty-three, twenty- 

 six, and twenty-eight days respectively. 



(b) Four fowls were fed on polished rice and given an addi- 

 tional daily dose of 5 drops of syrup of the iodine of iron U. S. P. 



Two fowls developed neuritis on the twenty-eighth and thirty- 

 sixth day respectively. 



"(c) Four fowls were fed on polished rice and given an addi- 

 tional daily dose of 1 grain of thyroid extract (tablet of Bur- 

 roughs Wellcome and Company). 



All 4 fowls developed neuritis in twenty-two, twenty-three, 

 twenty-four, and twenty-five days respectively. From this ex- 



