DUCTLESS GLANDS 143 



injection of adrenalin, by excision of the pancreas or by a lesion of the 

 islands of Langerhans in that organ. On the other hand, an increased 

 tolerance for carbohydrates (obesity) occurs after destruction of the 

 posterior lobe of the pituitary bod}'', as well as in myxoedema or after 

 thyroidectomy; increased blood pressure follows upon injection of the 

 pituitary, adrenal, placental and kidney extracts; lactation is accele- 

 rated by injection of extracts of the thymus, pineal and pituitary bodies 

 and the corpus luteum (ovary) ; the pupil is dilated by extracts of the 

 thymus, pituitary, pancreas, suprarenals, kidney, sexual glands, liver 

 and muscle. Effects of this kind are analogous to the mystifying 

 " enharmonic cross relations " in modern music, in which the same note 

 (on the piano scale) is so employed that it is brought into relation with 

 two different tonalities. C sharp and D flat, G sharp and A flat pro- 

 duce the same sounds when given on the piano scale, although they can, 

 if necessary, be distinguished on stringed instruments, which render an 

 exact account of the difference in the number of vibrations. Similarly, 

 these apparently identical effects of the different ductless glands indi- 

 cate that their functions are correlated, that they are somehow concerned 

 in maintaining the hormonic equilibrium of the body. 



Concerning the mechanism of correlation, two prominent theories 

 have been advanced. The first is the doctrine of the hormones of 

 Bayliss and Starling (1902) in which the chemical control of the body 

 is assumed to be effected by means of hormones, or chemical messengers, 

 which pass from the various organs and ductless glands, via the blood- 

 stream, to other parts of the body, producing biochemical effects upon 

 irritable protoplasmic tissues. In the initial experiment of Bayliss and 

 Starling, the secretion of pancreatic juice following upon introduction 

 of acid into the duodenum was found to be not a local reflex, as had 

 hitherto been assumed, but due to the action of a hypothetical sub- 

 stance (secretin) discharged by the intestinal mucous membrane under 

 the influence of the acid and carried to the pancreas by the blood 

 channel. Many experiments, particularly those of Howell on the 

 coagulants and anticoagulants of the blood (thromboplastin and anti- 

 thrombin) indicate the existence of hormones. Adrenalin, iodothyrin 

 and pituitrin are the only hormones of the ductless glands which have 

 been isolated to date. 



The other theory is that of the clinicians and pharmacologists of 

 the Vienna school, Eppinger, Falta and Eudinger, which asserts that 

 the suprarenal and thyroid bodies act upon and are controlled by the 

 nerves of the sympathetic system, while the pancreas is similarly related 

 to all nerves acting upon smooth (involuntary) muscle and not origi- 

 nating from the chain of sympathetic ganglia. The two systems have 

 been termed "autonomic," because they seem to be detached from and 

 independent of the controlling impulses arising from the cerebro- 



