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A Summary of Further Experimental Researches on the Etiology 
of Endemic Goitre. (Second Series.) 
By Rospert McCarrison, M.D., R.U.J., M.R.C.P.(Lond.), Captain I.M.S., 
Agency Surgeon, Gilgit. 
(Communicated by Major Ronald Ross, C.B., F.R.S. Received November 25, 
1910,—Read February 2, 1911.) 
The object of the research was to test by further experimentation on man 
the accuracy of the results communicated to the Royal Society on 
November 26, 1908.* These results afforded evidence that goitre was due to 
a living organism of disease present in the water of goitrous localities, that 
the causal factor of the disease was destroyed by boiling, and that it 
inhabited, in all probability, the intestinal tract of man. 
I. Twenty-three individuals, of the average age of 22, consumed the 
suspended matter of goitre-producing water for periods of from 30 to 55 days. 
Of these, six showed an increase in size of the thyroid gland which persisted 
in a more or less well-marked manner up to the end of the experiments. 
Three others showed a thyroid hypertrophy of a transitory character. 
(See photos.) | 
ARTIFICIALLY PRODUCED GOITRE. 
Figures illustrating the artificial production of goitre by means of the suspended 
matter separated by filtration from goitre-producing water. The figure to the left of the 
observer represents the subject of the experiment before the consumption of suspended 
matter was commenced. The remaining figures represent the appearance of the subject 
thirty days later. Attention is directed to the subject’s method of fastening his neck- 
band, which had fitted comfortably before the experiment was commenced. 
* * Roy. Soe. Proc.,’ B, vol. 81, p. 31, 
