THE GLANDS: THYROID AND PITUITARY 59 



exhilaration, and then descend into a slough of despond from 

 which they feel themselves inextricable. They are always talk- 

 ing about the ups and downs of their mental states. Headache 

 and languor and fatigability, dry skin and lack of appetite for 

 food or exertion on one day or for one week, give way on the next 

 day, or for the next week, to an energetic gayety, and sweaty, 

 flushed skin, a prominent appetite for food and every sort of 

 activity. Driven to be forever on the go, for one period, in the 

 next they feel like lying down most of the day, with no inclina- 

 tion for any life whatever. The stage of depression may go as 

 far as a melancholia, the stage of stimulation as far as mania. 

 They may simulate manic-depressive or cyclic insanity. Some- 

 thing restrains them, and holds them bound as in a vise in the 

 one cycle. And then they are driven on beyond themselves by 

 some invisible whip in the next. 



Thyroid as Differentiator 



Besides the action of the thyroid as energizer, lubricator, and 

 growth catalyzer, it has a remarkable power as a differentiator 

 of tissues. It determines the embryonic etchings of the different 

 organs which in their totality comprise the unique individual. 

 Every multicellular animal must first have existed as a single 

 cell, the impregnated ovum. With the body and personality of 

 the ovum, the creature is one and continuous, literally something 

 the single cell has made of itself by sub-dividing and differenti- 

 ating. In the process, the cell mass often goes through stages 

 which stand out as individualities in themselves, that appear 

 on the surface absolutely unrelated. So the caterpillar and the 

 butterfly, to the naive child, seem as far apart as worm and 

 bird. In the case of the frog, the tadpole as a first sketch seems 

 completely an impossible and wild absurdity. Yet we know 

 that there is an orderly progression of events, a propagation of 

 cells, a forward going arrangement of chemical reactions, that 

 results in expansion and intricate complication of the organism. 

 Just what the forces at work in this most mysterious of all natural 

 processes are, has been an intellectual mystery that the best 

 minds of the race have attempted to get rid of with words like 

 pangenesis (Darwin). Words of Black (Mediterranean or 

 Greek and Latin) origin, as Allen Upward has named them, 

 always cover a multitude of ignorances. The glands of internal 

 secretion, here, as in so many other dark places, provide the open 



