PATHOLOGY 187 



I shall attempt to prove this in a few words, thereby taking an opportunity 

 of referring to related conditions, namely, to sporadic and endemic cretinism, 

 to infantile myxedema, and to the so-called cachexia strumipriva. 



Two observations stand out prominently like landmarks in the great num- 

 ber of physiologic and clinical experiments and communications which resulted 

 in the establishment of the importance of the thyreoid gland in the causation 

 of myxedema. First, the experiment of M. SchifE, the results of which were 

 for a long time discredited and even ridiculed, but at last completely proven. 

 In this experiment an animal was subjected to thyreoidectomy, which under 

 ordinary circumstances would have proved fatal, as SchifE had previously 

 shown in 1859. But SchifE found that the animal did not succumb if the 

 thyreoid gland were grafted into the abdominal cavity or under the skin, the 

 specific constituents of the gland being thus preserved for the organism. N"ext 

 came the important communications of Kocher and Eeverdin who observed 

 after the extirpation of the thyreoid gland in man a condition of general 

 cachexia with physical and mental phenomena which show a marked similar- 

 ity to the symptoms of myxedema just described, and also correspond accu- 

 rately to the phenomena developing in an animal affer extirpation of the 

 thyreoid. In other words cachexia strumipriva, produced experimentally or 

 (in man) as the result of an operation, is identical in nature with genuine 

 myxedema. Now since in both cases the same defect is present, namely, 

 absence of the thyreoid, it follows that the resulting insufficiency, that is, the 

 complete loss of function of the thyreoid gland, is to be looked upon as the 

 cause of these pathological phenomena. 



I cannot here discuss the difEerent phases which the evolution of this view 

 has undergone. But one stage at least I should like to bring into prominence, 

 for it shows how difficult the proper interpretation of an experiment may 

 sometimes be, and how obscured by complicating conditions. 



Some investigators did not succeed in producing the symptoms of cachexia 

 strumipriva (or, more correctly, cachexia thyreopriva, as we are not speaking 

 of the removal of a goiter) by thyreoidectomy, and consequently were justified 

 in doubting the causal relation of the thyreoid gland. Then Gley showed 

 that besides the great mass of the thyreoid there are in animals small, super- 

 numerary glands, which had already been anatomically descriljed by Sand- 

 strom. These extra thyreoids, if not removed together with the gland, per- 

 form vicariously the function of the latter. Only after this circumstance had 

 been taken into consideration could constant results be obtained. In the 

 same manner we may explain those observations (which, however, are in the 

 minority) which show that in some cases cachexia strumipriva did not follow 

 thyreoidectomy in man. This is because parts of the gland were not removed 

 at the operation or because a rapid reproduction of the gland took place. But 

 even a few isolated and trustworthy cases of this kind would not overbalance 

 the enormous number of positive observations to the contrary. 



But let us proceed a step further. All over the world, as is well known, 

 there are unfortunate individuals whose mental and bodily development is 

 retarded, so that they present a stupid and misshapen appearance. They are 

 called cretins, and their disease cretinism. From the fact that such ill-fated 



