THYROID INSUFFICIENCY 187 



pain in her breasts. The administration of thyroid Mastidynia 

 extract relieves the patient by producing a shorter ^u^iencj. 

 menstrual cycle. It appears not unlikely, therefore, 

 that the protraction of the menstrual cycle with the 

 accompanying mastidynia is due to a slight degree of 

 insufficiency in the thyroid. 



The thyroid secretion is associated with the integrity Thyroid 

 of the function of conception, just as it is with that of pregnancy. 

 menstruation. It is well known that the thyroid gland 

 enlarges in the early stages of pregnancy ; and the 

 enlargement is found to be due to the storage of colloid 

 in the vesicles. This change is probably associated 

 with the alterations in metabolism which occur in these 

 circumstances. 



A marked degree of insufficiency, such as is seen in 

 myxcedema, almost invariably leads to sterility unless it 

 be treated. Cases, however, have been recorded in which 

 pregnancy has occurred in minor or variable states of 

 ' this disease ; and in such circumstances an improve- 

 ment has usually been produced in the general condition 

 of the patient as the result of an increase in the thyroid 

 activity. 



There is another important point in regard to thyroid Thyroid 

 insufficiency — namely, its relation to the toxaemias of theToxjemias 

 pregnancy. of P^gnancy. 



Fischer 1 and Lange 2 many years ago propounded the 

 theory that the enlargement of the thyroid which occurs 

 during gestation is connected with a protective influence 

 on the part of the thyroid secretion against the toxic 

 elements that are elaborated in pregnancy. 



Such reasoning naturally led to the assumption, 

 advocated in this country by Nicholson 3 , which has 

 been taken up extensively by clinicians, that eclampsia 

 is due to thyroid insufficiency in the later months of preg- 

 nancy. It will be remembered that in my experiments 



1 Fischer, J., Wein. Med. Presse, 1895, vol. xxxvi, p. 1922. 



2 Lange, M., Zeitsch.f. Qeb. u. Gynak., 1899, vol. xl, p. 34. 



3 Nicholson, H. O., Scot. Med. Surg. Journ., Edin., 1901, vol. viii, 

 p. 503, 



