Liirliohydriite Metuholism in relation to tlie Tliyroid (Mand 6'i 



thyioifl ijlaud in the form of a powder was mixi'd w itli the fo(»d in the 

 iijornin<r and eveniiiir. Half a iiianune of dried thyroid was ifiven each 

 time. In some instances lialf a hjbe of a fresli sheep's i^hmd was given, 

 instead of half a <;ramme of the dried thyn^d, diiiini; part of the 

 experimental period. The dried thyroid powder had i)een prej)ared 

 recently in the laboratory from fresh inlands obtained from the slaui,diter- 

 house. It is in our experience essential for experimental purposes to use 

 a thyroid preparation made recently from fresh thyroids, and under 

 personal supervision, if one wishes to obtain reliable and constant results. 

 It was noted as an important point that the thyroid-fed animals were not 

 more active during the periods of observation than the normal animal. 

 They also were asleep during almost the entire period of observation, 

 except the last hour. 



The results are represented graphicall}' in tigs. 1-11. Figs. 1-6 

 represent the curves of the respiratory quotients from the third to the 

 eighth hour after a meal of 10 grammes of bread and milk. In these 

 figures the interrupted lines labelled " N " represent the results obtained 

 with the normal animal before the administration of thyroid gland. The 

 curves obtained on different days are labelled N^, No, and N3 respectively. 

 The solid black lines labelled " Th." represent the results obtained in 

 animals fed with thyroid gland. The numbers attached to the letters 

 ■ Th." indicate the number of days during which th3'roid-fee(ling has been 

 maintained. Thus " Th. 5 " means that the animal has been fed with thyroid 

 gland for the five days preceding the observations, the last dose being 

 given with the meal immediatelj^ preceding the observations. The dotted 

 lines labelled " R " represent results obtained in animals recovering from 

 the effect of thyroid- feedinor. Here again the number attached to the 

 letter " K " indicates the number of days after the last dose of thyroid has 

 been griven. 



Figs. 7-11 give graphically the amounts of COg excreted and O^ 

 absorbed in milligrammes in hourl}^ periods. The upper solid lines re- 

 present CO., excreted in milligrammes, the lower dotted lines represent the 

 O2 absorbed in milligrammes. The total amount of CO, excreted during the 

 whole six-hourly period is given in milligrammes underneath each curve. 



Further experimental details are given in the protocols appended to 

 this paper. 



The results obtained with the four rats in the normal .state (before the 

 administration of thyroid gland) may be considered together. They 

 agree in every respect with the observations of Pembrey and Spriggs (6) 

 on the oaseous metabolism of normal rats. After a meal rich in carbo- 

 hydrates the COg excretion shows a marked rise and then gradually falls. 

 At the same time the oxygen excretion remains fairly constant. The 

 changes in the respiratory quotient are therefore mainly dependent upon 

 the changes in the CO.^ excretion : the quotient reaches its maximum in 

 the third hour after a meal, rising to about unity, when carbohydrates are 



