On the Experimental Production of Congenital Goitre. 325 



been due to influences quite outside the scope of the present experiment 

 (fig. 3). 



The kid born of the mother in the third class was perfectly healthy ; its 

 thyroid was palpable but there was no goitre. 



Amongst the nine control animals, therefore, six had offspring ; 66'6 per 

 cent, of kids born were living and healthy, 333 per cent, were stillborn, 

 while 33"3 per cent, were goitrous at birth. In neither of the two kids born 

 with goitre did the enlargement reach the size of the majority in Class A. 



Characteristics of the Foetal Goitre. 



(1) In all cases the congenital goitre of the offspring was markedly larger 

 than that of the mother, sometimes as much as 20 times as large. 



(2) Macroscopically they were of the appearance and consistency of normal 

 kidney. On section the gland resembled a solid organ such as the liver, the 

 cut surfaces freely exuding fluid which subsequent histological examination 

 showed to be composed largely of thin blood-stained colloid. 



(3) Microscopically the gland presented the appearances characteristic of 

 very active secretion. The capillaries were congested, the alveoli small and 

 lined with high columnar epithelium, which was often so high as to almost 

 obliterate the acinar cavity. The cellular protoplasm was pale and 

 vacuolated, the nuclei large and spherical, or small and irregular-shaped 

 representing recent division forms. Evidences of nuclear division, of cell- 

 multiplication and of new acinar formation were everywhere numerous. 

 Thin, pale-staining colloid secretion filled the minute acini, permeated the 

 interstices between the parenchyma cells and distended the lymph spaces, in 

 some of which considerable accumulations of a more deeply-staining colloid 

 were to be seen. 



(4) Cultural methods of examination, both aerobic and anaerobic, showed 

 these goitres to be invariably sterile. 



Discussion and Conclusions. 



Eeturning now to a consideration of the factors to which the differences of 

 results in these animals are attributable, we have first to consider whether 

 the free contact of those in the first class may have influenced the results. 

 We have seen that goitre appeared in two of the eight control mothers of 

 Class B and congenital goitre in the offspring of both of them, although the 

 animals were prevented by their tethered position from intermingling one 

 with another ; such association is not a necessary factor, therefore, in the 

 development of either acquired or congenital goitre. It may possess a 

 favouring influence by increasing the infectivity of the site on which the 



