CHAP. XXXV.] THYROID. 5 L 9 



ner with the nervous system, and probably with the sympathetic. 

 Bergman thinks that this part of the supra-renal body may, per- 

 haps, bear a relation to the sympathetic, similar to that which the 

 pituitary body does to the brain. It is interesting to note, in con- 

 nection with this subject, that our friend, Mr. Brown-Sequard, has 

 observed congestion, and hypertrophy of the supra-renal capsules, 

 after injuries to the cord in the dorsal region. 



Dr. Addison has lately published an account of several very 

 interesting cases of disease of the supra-renal capsules, associated 

 with " anaemic general languor and debility, remarkable feebleness 

 of the heart's action, irritability of the stomach, and a peculiar 

 change of colour in the skin." * 



Thyroid. The thyroid body, or gland, as it is sometimes called, 

 is a soft, and very vascular organ, situated upon the lateral aspect 

 of the upper part of the trachea, as far upwards as the sides of the 

 larynx. It consists of two lateral lobes, united by a thin narrow 

 portion, which has a similar structure to that of the gland itself, 

 extending across the front of the third or fourth rings of the 

 trachea, and known as the isthmus. The middle lobe, which varies 

 somewhat in position, is a thin process, extending upwards from 

 the isthmus, or one of the lateral lobes, and often reaches as high 

 as the hyoid bone, to which it is attached by loose fibrous tissue ; 

 indeed, this process itself is not unfrequently composed of fibrous 

 tissue only, and sometimes contains a few fibres of the thyro-hyoid 

 muscle. 



The thyroid body itself, is made up of a vast number of small 

 lobules, which are aggregated together in larger globular or oval 

 masses, of which the entire substance of the gland is composed. 

 These are all surrounded by, and connected together with, areolar 

 tissue, and each subdivision itself consists of a number of small 

 closed vesicles, between which the vessels ramify, also closely in- 

 vested with areolar tissue, varying considerably in size, and con- 

 taining fluid, or a thick gelatinous matter. 



Each vesicle may, therefore, be described as consisting of a 

 fibrous coat, composed of areolar tissue, internal to which there 

 exists a delicate basement membrane, lined by cells of epithelium, 

 which vary somewhat in character, but usually are seen as poly- 

 gonal, or almost circular cells of a faintly granular appearance, and 

 having a nucleus, which, however, is by no means invariably pre- 



* " On the constitutional and local effects of Disease of the Supra-renal 

 Capsules," by Thomas Addison, M.D., Senior Physician to Guy's Hospital, 

 1855. 



