54 



Herring 



body-weight shows greater variation than in the normal, the lowest figure 

 being 0-032 nig. in the eighth rat, and the highest 0070 mg. in the seventh 

 and tenth. The average is 0*052 mg., which, compared with the average 

 normal amount of 0*034 mg., shows an increase of 0-018 mg. per 100 grm. 

 body-weight, or nearly 53 per cent. 



In the second series of thyroid-fed animals (Table IV.) the amount of 

 adrenalin is similarly increased. The average adrenalin content is 0-067 

 mg. compared with 0048 mg. in the normal. Per 100 grm. body-weight 

 the adrenalin is 0-049 mg. as against 0*033 mg. in the normal. This is 

 an increase in the adrenalin of the thyroid-fed rats of 0*016 mg., or nearly 

 50 per cent. 



Table IV.— Second Series. Rats of the same Age fed on Bread 

 AND Milk +(t-2 Grm. Fresh Ox Thvroid daily. 



9. 



10. 



''= ^^ -M 



as 2^ 40 

 O jj s .£P 



-^ •- e: -s 



aJ E o 



is- « r- 



-' ft 



34-95 



24-42 

 38-00 

 32-62 

 22 06 



3 tb 



11. 



tble 



•73 



o 



S S-" 



0-046 

 0-055 

 0-088 

 0-083 

 0-064 



30-38 0*067 



5 tc^ 



■rf o tU 



0-045 

 0-042 

 0-056 

 0-059 

 >044 



12. 





QJ _i .- « 



4) - 



•128 

 •172 

 •147 

 ■180 

 •200 



0-049 



0-165 



In both series of thyroid-fed animals the percentage amount of 

 adrenalin in the suprarenals is reduced, the figures being 0*191 against 

 0*224 normal in the first series, and 0-165 against 0*196 normal in the 

 second series. The adrenalin increases with the increase in size of the 

 suprarenals, but not to the same extent. It would seem, therefore, that 

 there is a relatively greater hypertrophy of the non-adrenalin-forming 

 tissue in the suprarenals. The animals examined received thyroid until 

 the day before they were killed. If the increase in adrenalin is com- 

 pensatory to the increased] intake of thyroid, as appears most probable, it 

 is not unlikely that the suprarenals would show an even higher adrenalin 

 content had the thyroid-feeding been discontinued for a longer interval 

 before the animals were killed. One animal in each of the thyroid-fed 

 groups died some time before examination. Both of these had the 

 heaviest suprarenals recorded, viz. 60 mg. One of them, No. 3 in Table lY., 

 was not examined until a considerable time had elapsed, and a certain 

 amount of its adrenalin must have disappeared in the interval. From 



