314 C. P. HOWAKD 



ing a pathological interaction between the brain and the thyroid. This 

 pathological interaction may be broken by diminishing the thyroid output, 

 thus allowing the brain to regain normal control, or by securing physio- 

 logical rest, which simultaneously secures normal control of the brain, 

 which in turn will give the thyroid the opportunity of returning to the 

 normal." . . . "Because the conception here presented relates wholly to 

 the release of energy it is designated the 'Kinetic Theory.' ' This ro- 

 mantic theory is of great interest and merits some consideration coming 

 as it does from such a well known student of the disease. To most of us, 

 however, it appears too theoretical and lacking in scientific confirmation. 

 In conclusion, we would only agree with Barker that there are many and 

 diverse causes of exophthalmic goiter ; some, like sex, habitat and heredityj 

 are predisposing; others, like shock and worry, may precipitate a latent 

 hyperthyroidism ; while infection may act as a direct exciting cause in 

 some cases. The pathogenesis is not always the same ; it may be of nerv- 

 ous, toxic, infectious or metabolic origin. A more exact statement is not 

 possible in the present condition of our knowledge. 



Symptomatology. The symptoms are manifold and involve every 

 system in the body, but the five cardinal symptoms are: (1) the goiter, 

 (2) the exophthalmos, (3) the tremor, (4) the tachycardia, and (5) the 

 increased metabolism. The relative frequency of these five main symp- 

 toms is as follows: Tachycardia in 100 per cent, tremor in 99 per cent 

 (Sattler), struma in 96 per cent, increased metabolism in 88 per cent 

 (A. Kocher), and exophthalmos in 77 per cent (Pende). Barker (&) at 

 tempts to classify the various symptoms apart from (i) the struma, 

 under: (ii) those referable to disturbances of autonomic innervation ; 

 (iii) disturbances of metabolism ; (iv) disturbances of the endocrin glands 

 other than the thyroid; (v) cerebral and (vi) hematopoietic disturbances. 



While admitting that this subdivision entails some repetition and is 

 by no means ideal, we have adopted it in this article as perhaps the most 

 useful in our present state of knowledge, or rather of ignorance, of the 

 many-sided disease. 



The Goiter or Struma 



Size. The thyroid gland is nearly always enlarged, though in general 

 the enlargement is not great. G. II. Murray has classified this enlargement 

 as: (1) slight, when tlie gland can be distinctly felt; (2) moderate, when 

 it can bo seen and felt; (3) considerable, when it is obvious and disfigur- 

 ing, and (4) enormous, when it more nearly approaches the endemic 

 goiter. The majority of the cases fall under the first two groups; about 

 one-sixth are of considerable size: the enormous goiters are extremely 

 rare, though .Murray (d) reported one case in which the neck measured 

 twenty-three inches in circumference and Dock (a) another of nineteen 



