E. B. Hart and H. Steenbock OL? 
thyroid of the mother producing hairless pigs, although it does 
serve to give the normal sized thyroid to the fetus. As an illus- 
tration, a thyroid from a mother that had always produced hair- 
less pigs, but in the last gestation had received potassium 
iodide, weighed when fresh 112 gm. and was translucent and 
gelatinous in appearance, indicating a richness in colloid; it con- 
tained 0.62 per cent of iodine in the dry matter, which weighed, 
33 gm., but the fresh thyroid was of the size of a man’s fist 
while the normal 300 pound pig’s thyroid approximates the size 
of a walnut. 
It has already been made clear by the work of Marine’ and 
others that the enlarged thyroid, accompanied by the symptoms 
of myxedema and dermal malnutrition, is a thyroid low in iodine. 
This enlarged vascular system of the thyroid gland is directly 
related to an automatic attempt on the part of the organism to 
furnish a blood of probably lower iodine concentration to the 
thyroid at a greater rate, in order that this gland may meet the 
requirements for adequate colloid building. This is exactly the 
condition of the thyroid in the hairless pig. Its iodine content 
is either but a trace or none. 1 day old pigs with scanty hair 
coat contained 0.02 to 0.05 per cent of iodine in the dried thyroid, 
while the thyroid from the dead and hairless pigs contained in- 
estimable quantities of iodine. The iodine content of the nor- 
mal dried thyroid of 1 day old pigs varies from 0.1 to 0.6 per 
cent. Our own experiments, therefore, confirm in every respect 
the belief that there is a close relation between the hairless pig 
malady and the iodine assimilation by either intestine or thyroid 
of the mother. 
After we had produced hairless pigs by the above ration, the 
same sows were fed during the second gestation period a ration 
consisting of 33 parts of corn, 33 parts of oats, and 33 parts of 
alfalfa. On this ration dead and hairless pigs were again pro- 
duced. With these mothers, once there had been induced serious 
derangement, through the use of the first ration, of either in- 
testinal absorption or thyroid metabolism, the introduction of a 
lower protein level and larger amount of roughage did not act 
as a corrective. Bearing in mind the possibility that alfalfa 
itself was a contributor to this disturbance the sows were car- 
ried through a third gestation on a ration of 33 parts of corn, 33 
