208 ADDISON'S DISEASE 



substance which reaches the blood, and gives to the muscles the degree of 

 tension necessary for their functions. 



In a similar manner Cybulski and Szymonowicz proved the rise in blood- 

 pressure (by contraction of the vessels) and the strengthening of the cardiac 

 activity resulting from injections of suprarenal extract. But upon further 

 investigation (after severing the vagus and spinal cord, injecting atropin, 

 etc.) they obtained results which appeared to favor, not a peripheral action 

 of the extract, but an influence upon the central nervous system, particularly 

 the vasomotor centers of the cord. They also found marked irritation of the 

 respiratory center. They therefore assume that the secretion furnished by 

 the adrenals to the blood is intended to maintain the tonus of the cardiac, 

 vasomotor and respiratory centers. But the majority of the later investiga- 

 tions have favored the assumption of a peripheral action of the adrenal 

 extract. Only v. Cyon believes from his investigations that the rise in blood- 

 pressure depends for the most part upon an irritation of the vasomotor cen- 

 ters. On the other hand, the researches of Velich favor the view that the 

 vascular contractions which he observed after injection of adrenal extract into 

 the tongue, conjunctiva, ear, intestine and kidneys depend upon an influence 

 of the extract upon the peripheral vascular apparatus as well as upon the 

 co-operation of spinal vaso-constrictor centers. Biedl obtained, after complete- 

 destruction of the spinal cord, marked rise in blood-pressure by intravenous 

 injections of suprarenal extract, so that an irritation of the peripheral appa- 

 ratus may be assumed. Gottlieb, according to whom the increase in blood- 

 pressure depends principally upon a strengthening of the cardiac activity, 

 after investigations in chloralized animals, refers this to an energetic irrita- 

 tion of the motor ganglion groups which dominate cardiac movement. Lewan- 

 dowski has further demonstrated in a convincing manner a peripheral action 

 of the injected suprarenal extract upon the smooth muscles of the eye and of 

 the orbit (dilatation of the pupil, prominence of the bulbus oculi, etc.), 

 which is parallel to the vascular action. Finally I must mention the local 

 vaso- constricting action of the suprarenal extract which has been lately recog- 

 nized, and which has been used therapeutically upon the conjunctiva (by 

 advice of Darier), upon the larynx and nasal mucous membrane, and in 

 intestinal hemorrhages. 



In several of the investigations it has been proven that the adrenal venous 

 blood acts similarly to the extract (Cybulski, Dryer). The rise in blood- 

 pressure which is thus attained is usually very decided. In some cases it 

 has been raised above 300 mm. of mercury. After destruction of the spinal 

 cord, which reduces blood-pressure almost to zero, it can be raised to 160 mm. 

 by injection, and by repeated injection the pressure can be maintained for a 

 long time at from 90 to 140 mm. (Biedl). By using a very pure extract 

 recently produced by Moore and Purinton 400L00 of a gram is sufiicient 

 to maintain in a dog a persistent rise in blood-pressure of from 20 to 40 mm. 

 of mercury. 



Interesting observations have recently been made which show that injection 

 of adrenal extract into the abdominal cavity of guinea-pigs causes a destruc- 

 tion of red blood-corpuscles and produces in the spleen and lymph-glands 



