228 



NUTRITION 



FIG. 122 



out the leukocytes for their numerous functions. It has been suggested 

 that this organ in the fetus is the mother-tissue of all the lymphoid tissue 

 of the adult. The pituitary, sometimes called the hypophysis cerebri, 

 is a vascular mass situated at the base of the brain, and weighs only 

 one-half gram. According to Schafer and Vincent, extract of the pitui- 

 tary body causes a rise or fall in the blood pressure, an effect which is 

 probably brought about through the vagus. Its removal by disease 

 or mechanically causes sometimes death and sometimes the symptoms 



of acromegaly, a condition character- 

 ized by the aberrant overgrowth of 

 the bones of the face, skin, and ex- 

 tremities. The extract of the pitui- 

 tary body is said to be thirty times 

 stronger than that of the adrenals. 

 The adrenals, formerly called the 

 supra-renal capsules, secrete into the 

 circulation a substance which when in- 

 jected into a vein causes a powerful 

 vaso-constriction in the arterioles and 

 corresponding changes in the heart 

 itself. Less than eight hundred-thou- 

 sandths of a gram (0.00008 gm.) of 

 adrenalin chloride are sufficient to 

 affect the blood-vessels and heart of 

 a man for a short time. Vincent has 

 shown that the adrenals contain two 

 sorts of glands, those of the rind and 

 those of the interior. Of the function 

 of the former nothing is known. The 

 others are apparently concerned in 

 maintaining the tone of the muscu- 

 lature, perhaps by controlling the oxi- 

 dation of the tissues. The kidneys 

 appear to have as their contribution 

 to the agents of tissue-metabolism a 

 proteolytic enzyme which when carried 

 to the liver and perhaps to all the tissues 

 of the body leads to the production of urea. The internal secretion of the 

 spleen has been assigned many functions. All of these are complicated, 

 but none of them are at all established, and we need not even mention 

 them at this time. The testes and the ovaries apparently have substances 

 secreted by their epithelium which have a tonic influence over the nervous 

 system, especially in relation with the muscles. Injections of the extracts 

 of these two organs increases nervous vigor and muscular tone, and 

 semen exerts somewhat similar effects. 



Animal Heat. The third of the manifestations of the general metab- 

 olism which we shall specify is animal- or body-heat. It is a process 



The thyroid and the inner thymus of a 

 newborn child: 1, larynx; 2, trachea; 

 3, medial lobe; 4, lateral lobe; 5, apex of 

 the thyroid; 6, medial lobe; 7, lateral lobe 

 of the thymus. Natural size. (Rauber.) 



