362 THE INFLUENCE OF THE ORGANS ON ONE ANOTHER 



Recently attempts have been made in many ways to isolate the active sub- 

 stance of the thyroid,, and the iodothyrin produced by Baumann has been the 

 special object of numerous investigations. 



Iodothyrin is a brown-colored, amorphous substance which on heating swells 

 up enormously and is decomposed, yielding an odor suggestive of the pyridin 

 bases. It is almost insoluble in water, and is soluble with difficulty in alcohol. 

 It dissolves readily in dilute alkalies and is precipitated again on addition of 

 acids. Concentrated caustic soda with heat decomposes it slowly. The gland 

 can be boiled for days in a ten-per-cent sulphuric acid without destroying its 

 iodothyrin. 



This substance gives none of the proteid reactions, but always contains phos- 

 phorus in organic combination (0.56 per cent P) and, what is most important, 

 at least 9.3 per cent iodine. Notwithstanding that it occurs in the thyroid gland 

 to the extent of only 0.3 per cent, iodothyrin has a marked effect on the symp- 

 toms following the suppression of the thyroid, even when administered in very 

 minute quantities. 



According to Baumann, iodothyrin occurs in the gland in combination with 

 proteid; and Ostwald has reached the conclusion that the so-called colloid of 

 the thyroid gland consists of two proteid bodies, only one of which, the thyreo- 

 globulin, contains iodine; the other is a nucleoproteid containing a carbohydrate 

 group. By boiling the former with ten per cent H 2 SO 4 , Ostwald isolated a 

 product containing 14.3 per cent I, which he regards as an extremely pure 

 iodothyrin. 



The entire yield of this substance calculated on the basis of iodine is, how- 

 ever, only about one-tenth of the iodine in the gland, and it is therefore doubtful, 

 as Blum and Tambach have remarked, whether iodothyrin occurs as a conjugant 

 with proteid in the gland, or whether it is not first split off by destruction of 

 the proteid molecule. 



A fuller presentation of the views expressed by different authors concerning 

 the nature and the mode of action of the thyroid substance is impossible here. 

 We may mention only the fact that S. Frankel, as well as Drechsel and Kocher, 

 Jr., have isolated two other substances of a basic nature which exert a well- 

 marked, though not very strong, favorable action on animals whose thyroid has 

 been removed. 



If a healthy animal be fed with a great quantity of thyroid, various symp- 

 toms of poisoning make their appearance, such as tachycardia, polydipsia, poly- 

 phagia, polyuria; the quantity of urea increases, sugar appears after some time 

 in the urine, and the animal falls off in weight. Likewise in men when thyroid 

 is administered as a medicine, in too large doses, excitement, abnormal sensa- 

 tion of heat, increased destruction of proteid, jaundice, albuminuria, cardiac 

 palpitation and cardiac weakness make their appearance. 



E. THE PANCREAS 



When the pancreas of a mammal (dog, cat, pig) is totally removed with- 

 out any accidental lesions, a severe diabetes (according to some authors in- 

 variably, according to others generally) ensues (v. Mering, Minkowski, de 

 Dominicis, 1889). 



The appearance of sugar in the urine does not always show immediately 

 after the operation. It appears sometimes sooner, sometimes later, but in- 

 variably increases in intensity within the next twenty-four hours, and as a rule 



