962 THE INTERNAL SECRETIONS 



roid, are markedly different from those produced by the removal of the 

 parathyroids. This general fact becomes apparent immediately if 

 the symptoms enumerated above are subjected to a re-examination. 

 It will then be noted that they arrange themselves in two groups, one of 

 which is characterized by disorders of metabolism, such as malnutri- 

 tion and cachexia, and the other, by defects of nervous function, such 

 as muscular tremors and tetany. Recent investigations have fully 

 confirmed this deduction so that it may be regarded as certain that 

 thyroidectomy gives rise to a state of malnutrition, terminating in the 

 condition of cachexia thyreopriva, while parathyroidectomy results in 

 muscular tremors and spasms, forming the clinical picture of tetania 

 parathyreopriva. Consequently, the combination of these two com- 

 plexes of symptoms cannot be due to an overlapping of the functions 

 of these two types of tissue, but must be caused by their simultaneous 

 destruction or atrophy. 



While no definite statements can be made at this time regarding 

 the manner in which the thyroid exerts its peculiar metabolic action, 

 it may be surmised that it develops a specific hormone which facilitates 

 the chemical reductions in other tissues, chief among which is the ner- 

 vous tissue. First of all, this agent increases the total metabolism, 

 as is evinced by a greater excretion of nitrogen, carbon dioxid and 

 phosphoric acid, and a greater consumption of oxygen. Upon this 

 fact rests the therapeutic value of thyroid feeding in obesity, but since 

 in this case the difficulty does not lie in the protein metabolism, thyroid 

 feeding as a remedial measure against adiposity in the absence of an 

 actual inactivity of the thyroid is a dangerous procedure. It may 

 produce organic defects of the heart and other pathological lesions. In 

 this connection it should also be noted that the feeding of animals 

 with excessive amounts of meat may give rise to goiter and rickets, 

 and that this outcome may be prevented by the simultaneous ingestion 

 of milk, bread and bones. No definite explanation can be offered for 

 the hypertrophy and hyperplasia of the thyroid occurring during the 

 menstrual period and pregnancy. It cannot be doubted, however, 

 that it indicates a close functional correlation between the different 

 endocrine organs, and offers a plausible explanation for the peculiar 

 metabolic and nervous symptoms exhibited by women during these 

 periods. 



The picture of tetany following the removal of the parathyroids, 

 is very similar to that obtained in infantile tetany, the convulsions in- 

 cited by gastro-intestinal disorders, eclampsia, and other conditions. 

 It consists in a gradually increasing stiffness or rigor of the entire body, 

 trembling, clonic and tonic spasms of the muscles, as well as a loss of 

 muscular coordination and strength. The body-temperature rises, 

 the frequency of the heart and respiration is increased, whereas weight 

 is lost rapidly. This tetany may be mitigated or even abolished by 

 the administration of sodium bicarbonate, alkalies, calcium salts ^ or 

 ^ Macallum and Voegtlin, Johns Hopkins Univ. Bull., 1908. 



