THE THYEOID AND PARATHYROID BODIES 957 



along the aorta and along the arches of the gills. If we confine our- 

 selves, therefore, to the carnivora and include in this discussion the 

 symptoms caused by the enucleation of the parathyroids, the following 

 clinical picture is obtained/ 



The features are swollen and imperfectly outlined, owing to an 

 edematous condition of the skin which in turn is caused by an accumu- 

 lation of mucin in the subcutaneous connective tissue. Latier on, the 

 bloated appearance of the skin is aggravated by a certain roughness 

 and dryness, which finds its origin in the cessation of the cutaneous 

 secretions and eventually gives rise to a coarseness and falling out of the 

 hairs. This infiltration also affects the mucous membranes, and 

 eventually involves the respiratory passage and conjunctional sacs 

 (myxedema). The animal loses weight steadily, and finally enters 

 a condition of pronounced malnutrition, the so-called cachexia thyreo- 

 priva (strumipriva). But these purely metabolic disturbances which 

 prove that thyroidectomy renders the animal unfit to utilize its food, 

 are invariably associated with others, indicating a severe intoxication of 

 the nervous system. To begin with, it is observed that the muscular 

 contractions become clonic in their character, then tetanic and lastly, 

 spastic. This leads to a marked muscular rigidity and contracture, 

 and finally to a weakness as well as a motor and sensory paralysis of 

 the entire body. As the anterior and posterior extremities become 

 weakened and are no longer able to support the trunk, the animal is 

 forced to assume the position usually occupied by it during sleep. The 

 muscular tremors are gradually intensified and become more general 

 in their character, terminating eventually in severe convulsions and 

 death. Although the higher nerve centers appear to retain their func- 

 tion for a relatively long period of time, their irritability is gradually 

 diminished, which renders the animal stupid and very apathetic. 

 Death usually results in the course of 9 to 12 days. 



Cretinism, Mjrxedema and Hyperthyroidism. — Keeping the char- 

 acter of the symptoms just cited clearly in mind, we are now in a better 

 position to analyze the clinical pictures of cretinism, myxedema, 

 hyperthyroidism, exophthalmic goiter, and the conditions forming the 

 basis of Basedow's disease. In a general way, it may be said that man 

 is subject either to a diminished or an increased function of the thyroid 

 gland, or, in other words, to a deficient or an excessive formation of 

 this internal secretion. 



(a) Cretinism or infantilism is due either to an imperfect development of the 

 thyroid gland or to its atrophy in later years. The infant so afflicted presents a 

 dwarfed appearance, because the growth of the bones and soft parts has been 

 checked. The abdomen is large and pendulous, while the legs are poorly formed 

 and seem scarcely able to support the weight of the trunk. The face presents a 

 swollen appearance and imperfectly outlined contours. The hair is coarse and 

 scanty and the skin thick and dry. Mentally, the cretins are far behind children 

 of the same age, in fact, their intelligence frequently borders upon imbecility and 

 idiocy. Their movements are clumsy and unsteady. In many instances, this con- 

 dition of infantile myxedema or cretinism resembles very closely true dwarfism, 



