177 



oxalic acid only. Several other tests e. g. the biuret and nitrate were 

 made but in each case negative results were obtained. 



The residue on the filter paper was tested for uric acid which is 

 insoluble in alcohol but the results were equally unsuccessful. I ob- 

 tained a yellow precipitate with ammonium molybdate and a faint 

 one with silver nitrate which might indicate the presence of soluble 

 phosphates. 



Physiology. 



I took sixteen glands and after mincing and pounding them with 

 sand I added one per cent sodium carbonate solution and left them 

 at a temperature of 33" C for twenty hours. After filtering, a 

 brownish, slightly cloudy liquid was obtained. This extract showed 

 clearly the presence of a ferment similar to amylopsin which converted 

 starch into sugar, and also a fat-splitting ferment similar to the lipase 

 of pancreatic secretion. These were previously fount! by Blanchard (3). 



I also made glycerine extracts of many glands and have tested 

 them for a ferment such as Trypsin. I have however with these 

 extracts never been able to obtain any digestive action on fibrin 

 in alkaline solution though I have in some cases found that the ex- 

 tract will dissolve fibrin in a 0.2% solution of hydrochloric acid. 

 However in these cases this power seems to be shared to an equal 

 extent by the alimentary tract in the immediate neighbourhood as also 

 by the spiral intestine. This is in agreement with the results obtained 

 in the Perch and other fresh water fish by Decker (5) in 1887 and by 

 Krukenberg (7) in 1877. In many other cases the extracts made of 

 the intestine and its appendages seemed to be quite inactive. 



Where the optimum temperature for the action of the various 

 ferments has been tested it has been found to be from 40 " C to 43 '^ C 

 — that is a little higher than that found by Blanchard (3). 



I hope shortly to publish a more extended account of the structure 

 and functions of the alimentary canal in general both in Elasmobranchs 

 and other fish. 



In conclusion I wish to express my thanks to Dr. Marett Tims 

 not only for having suggested the line of research but also for his help 

 and interest throughout the progress of the work. 



Zoological Laboratory Bedford College (University of London), 

 December 17th, 1907. 



Since the manuscript of the above passed out of my hands, my 

 attention has been drawn to a paper recently published by Sullivan 



Auat. Anz. XXXII. Aufsätze. 1^ 



