

4i 4 TEXT-BOOK OF PHYSIOLOGY. 



and in some unknown way influences favorably tissue metabolism. 

 This view of the function of the thyroid is supported by the fact that 

 successful grafting of a portion of the thyroid beneath the skin or in 

 the abdominal cavity will prevent the usual symptoms which follow 

 thyroidectomy. The same result is obtained by the intravenous 

 injection of thyroid juice or by the administration of the raw gland. 

 It was shown by Murray that myxedematous patients could be bene- 

 fited, and even cured, by feeding them with fresh thyroids or with 



dry extract. 



The chemic features of the material secreted and obtained from 

 the structures of the thyroid indicate that it is a complex proteid con- 

 taining iodin, which, under the influence of various reagents, under- 

 goes cleavage, giving rise to a non-proteid residue, which carries with 

 it the iodin and phosphorus. The amount of .iodin in the thyroid 

 varies from 0.33 to i milligram for each gram of tissue. To this 

 compound the term thyroiodin has been given. The administration 

 of -this compound produces effects similar to those which follow the 

 therapeutic administration of the fresh thyroid itself: viz., a diminu- 

 tion of all myxedematous symptoms. In normal states of the body, 

 thyroiodin influences very actively the general metabolism. It gives 

 rise to a decomposition of fats and proteids and to a decline in body- 

 weight. In large doses it may produce toxic symptoms: e. g., in- 

 creased cardiac action, vertigo, and glycosuria. 



The Pituitary Body. This is a small body lofoed in rhp 

 sella turcica of .'t^ sphenoid ...bone. It consists"' oTan anterior Tobe, 

 somewEat red in color, and a posterior lobe, yellowish-gray in color. 

 The former is much the larger and partly embraces the latter. The 

 anterior lobe is developed from an invagination of the epiblast of the 

 mouth cavity, and consists of distinct gland tissue. The posterior 

 lobe is an outgrowth from the brain, and is connected with the 

 infundibulum by a short stalk. It has been suggested that the term 

 infundibular body be reserved for the posterior lobe, and the term 

 hypophysis cerebri for the anterior lobe. This distinction appears 

 to be desirable, inasmuch as in their origin and structure they are 

 separate and distinct bodies^ 



Removal of the hypophysis cerebri, or the pituitaiy body, is always 

 followed by a fatal result, preceded by symptoms not unlike those 

 . whicE follow removal of the thyroid: viz., anorexia, tremors, spasms, 

 etc. Degeneration of the pituitary body has been found in connection 

 with a hypertrophic condition of the bones' of the face and extremities, 

 to which the term acromegalia has been given. 



Intravenous injecSSh of an extract of the pituitary increases 

 the force of the heart-beat without any change in its frequency, and 

 causes a rise of blood-pressure from a stimulation of the arterioles 

 chafer and Oliver). The material secreted by the pituitary has 





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