66 



Mr. S. Vincent. 



The extracts employed were obtained in various ways. Some were 

 prepared by pounding the glands with sand and normal saline in a 

 pestle and mortar, and subsequently filtering-. Others were alcoholic, 

 while still others were got by boiling for a short time a certain 

 quantity of the material in a known amount of normal saline and 

 filtering. In all cases care has been taken to obtain the solution 

 free from particles before injection or perfusion. ' 



For intravenous injection an extract of 1 in 25 of the fresh, moist 

 gland has been usually employed. I have not ascertained the mini- 

 mal effective dose, but 1 c.c. of such an extract (= O04 gram of 

 the fresh gland) from the active glands produced a powerful effect. 



The results obtained by these two methods are quite harmonious. 

 I had anticipated the possibility that the extract from a fish might be 

 inactive upon a mammal, but it will be seen that this anticipation 

 was unfounded. There is in all cases, where " medullary " substance 

 has been injected, very striking evidence of contraction of the 

 arterioles throughout the body. This was made manifest when 

 using dogs or cats with the mercurial kymograph by an enormous 

 rise of blood pressure (see fig. 1). In the perfusion experiments 

 upon toads the result was seen in an almost complete cessation of 

 flow of fluid through the blood-vessels (see Experiment 1). When 

 " cortical " substance was employed little or no effect in these direc- 

 tions was obtained (figs. 2 and 3, and Experiments 1 and 2). It i& 

 true there was always a slight rise of blood-pressure or a small 

 diminution of flow of fluid when extract of interrenal was used 

 (Experiment 1 and fig. 2), but an explanation of this is, I believe, 

 readily to be found. The extracts from the suprarenals of Teleosts 

 have always given negative results when tested by both methods 

 (see Experiment 2 and fig. 3). 



The effect of the active principle upon the arterioles is due to a direct 

 action upon the muscular tissue of the blood-vessels, and is not in any 

 way connected with the action of the central nervous system. This 

 is perfectly clear from the fact that the effects are well marked in the 

 toad when brain and spinal cord, have been destroyed by pithing. 

 Oliver and Schafer found this to be the case with mammalian 

 suprarenal extract, though Szymonowicz and Cybulski maintain 

 the contrary. The results of Oliver and Schafer have since been 

 completely confirmed by Velich.* 



Fig. 1 shows the most typical effect ; the lever rises gradually at 

 first, then afterwards almost vertically. In some cases the pressure 

 was too high to be recorded, as the mercury escaped from the end of 

 the manometer. The effect passes off after a variable period, and 

 the blood-pressure returns to normal. There is no need to give 

 further details, but it will be sufficient to say that the experiments 

 * « Wien. Med. Blatter,' Nr. 15, bis 21, 1896. 



