i INTERNAL PROTECTIVE SECRETIONS 13 



number of leucocytes in excess of the normal (as compared with 

 the erythrocytes), and that perivascular lymph spaces exist round 

 them, which are often wider than the vessels and show a network 

 of connective filaments coming from the adventitia. They regard 

 these perivascular spaces as the outflow of the parathyroid secretion, 

 masses or lumps of a granulated substance being sometimes noted, 

 which stain like colloidal substance. 



IV. The physiology of the thyroid and the modern conception 

 of it as a glandular organ of internal secretion, indispensable to 

 normal life, is derived from surgery. After the introduction of 

 antisepsis, thyroidectomy was attempted in cases of goitre, and the 

 effects observed. As early as 1856-57, indeed, M. Schiff, in a series 

 of experiments on total thyroidectomy in animals, noticed that it 

 was frequently fatal in dogs after the first week, in guinea-pigs 

 somewhat later, although death could not be referred to the state 

 of the wound nor to lesions of the recurrent branch of the vagus, 

 nor of the cervical sympathetic. But he gave no adequate account 

 of the phenomena by which death is preceded, and abandoned his 

 researches, owing probably to the inconstancy of the results, since 

 he found that rabbits, some rats, a dog, and several guinea-pigs 

 survived the operation.. It was not till after the publications of 

 the two Genevese surgeons, Reverdin, and Kocher, a surgeon in 

 Berne (who in 1882-83 described the effects of total excision of 

 goitre), that these experiments were repeated. The credit of 

 directing the attention of physiologists to this important subject 

 is accordingly due to surgery. 



We will first review the phenomena of deficiency of the thyroid 

 gland, starting with all the best-known surgical cases, which may 

 be regarded as so many physiological experiments performed on 

 man. 



Patients who have undergone total thyroidectomy, and have 

 already been discharged from the hospital as cured, experience the 

 initial symptoms of glandular deficiency either at once or at 

 latest some weeks after the operation. They feel weak, complain 

 of heaviness of the limbs, and more or less diffuse dull pains, 

 particularly in the legs, which may become acute and assume the 

 character of pains in the bones. 



Other more serious symptoms are gradually associated with the 

 preceding. After four to five months the face and the extremities 

 swell and become cold, the muscles are torpid, sometimes rigid, 

 often exhibiting muscular tremors, and are incapable of carrying 

 out any delicate manual acts with precision. At first the swelling 

 is variable ; it is more pronounced in the morning than in the 

 evening, but steadily increases, until it becomes permanent. It is 

 not ordinary oedema, in which percussion with the finger leaves 

 a depression ; it is a hard and elastic swelling. It is specially 

 localised in the hands, feet, and face, where it produces a 



