336 Capt. R. McCarrison. Further Expervmental [Nov. 25, 
II. Twenty-three individuals, of the average age of 22, consumed the 
boiled suspended matter of goitre-producing water for periods of from 
30 to 55 days. Of these, none showed the slightest tendency to inerease 
in size of the thyroid gland. 
III. Seven individuals, of the average age of 22, consumed the filtered 
goitre-producing water concurrently with the subject consuming the sus- 
pended matter of the same water. Of these, none showed the slightest 
increase in size of the thyroid gland, while three of them, who were 
sufferers from incipient goitre, showed a marked diminution in size of the 
organ. 
It is pointed out that the enlargement of the thyroid gland which can be 
experimentally produced in this way is not great, nor is it progressive under 
the conditions of the experiments. The development of goitre is believed to 
be largely dependent on certain secondary factors which favour the action 
of the unknown causal factor of the disease. 
These factors are classed as: (1) those directly influencing the thyroid 
gland, rendering it less able to counteract the action of the toxic agent of 
goitre without undergoing hypertrophy; (2) those which favour infection ; 
(3) those which favour the action of the virus of the disease at the time of 
its entry into the body. 
IV. The curative action exercised by the lactic ferments when applied to 
the treatment of cases of incipient goitre is believed to afford additional 
proof of the view that the organism responsible for the production of goitre 
has its habitat in the intestinal tract of man. (See photos.) 
VY. Experiments were carried out on dogs to test the possibility of the 
communication of the disease to these animals by means of watery extracts 
from the feces of goitrous individuals. The results were negative. 
It is concluded that— 
1. There exists in suspension, in waters which are known to be goitre- 
producing, an agent which is capable of initiating an hypertrophy of the 
thyroid gland. 
2. This agent is destroyed by boiling and is removed from the water by 
filtration. ; 
3. This agent is, therefore, either a living organism or a chemical substance 
the noxious properties of which are destroyed by heat. 
4. The incubation period of experimentally produced goitre is usually 
about 10 to 15 days. 
5. Goitre can be cured by the administration of intestinal antiseptics. 
The lactic ferments exercise a curative action when applied to the treatment 
of incipient goitres. 
