568 GEORGE S. TERRY 



scopical examination of the epiphysial line showed specific 

 degeneration, consisting in a reduction of the normal cell pro- 

 liferation, combined with vesicular swelling of the cartilage 

 lacunae and shrinkage or even partial destruction of the cells. 

 Eiselsberg ('95) found that, in sheep whose thyroid had 

 been removed at the age of ten days there was a conspicuous 

 retardation of growth and a high degree of derangement of the 

 processes of skeletal growth. In goats operated on three weeks 

 after birth the same author observed shortening of the bones of 

 the extremities, marked shortenings of the frontal part of the 

 head, the occipital part appearing exaggerated by comparison. 

 Similar results have since been obtained with dogs by Massaglia 

 ('07) and by Parhon and Goldstein ('09) with cats. So it seems 

 just to conclude that the arrest of growth of the skeleton is the 

 typical and invariable result of the absence of the thyroid func- 

 tion in both carnivora and herbivora. The most constant 

 symptom says V. Bruns 1 in man as well as in animals is a re- 

 markable disturbance of growth. The arrest of development 

 produces a dwarf like appearance of the individual due to im- 

 perfect endochondral ossification. The enclosed epiphysial 

 line may be seen in skiagrams and post mortem examination 

 shows that the ossification of the ends of the epiphysis is ex- 

 tremely deficient while the periosteal bone formation is un- 

 disturbed. So we see that a comparatively large amount of 

 work has been done upon the effects of the removal of the thy- 

 roid gland in mammals and even its effects have been studied 

 to a greater or lesser extent in man, but up to this time no at- 

 tempt has been made to work out the effect upon the develop- 

 ment of the skeletal system produced by the removal of this 

 gland in Amphibians. An excellent review of the results and 

 interpretations of various workers has been given by Biedl 

 in his recent book on the "Internal Secretory Organs," so that it 

 will be unnecessary to devote any more space here to the discus- 

 sion of the general problem. 



1 (Quoted from Biedl; Internal Secretory Organs. 



