20 BULLETIN OF THE BUREAU OF FISHERIES. 
(1899), on the contrary, found that the bile even doubled the action of the pancreas, 
and that this action was not lost by boiling, and Delezenne (1902) verified, in the 
main, Bruno’s work, but declared that bile does not activate inactive pancreatic juice. 
What part the bile plays in activating the pancreas is not yet fully decided. 
The spleen has also been claimed to play a certain part in digestion. Schiff 
(1862), Gachet and Pachon (1898), Bellamy (1901), and Mendel and Rettger (1902) 
have shown that the spleen when congested during digestion increases the proteolytic 
power of the pancreas. On the other hand, Heidenhain (1883), Ewald (1878), and 
Hammarstein (1901) do not find that the spleen had any action on pancreatic digestion, 
while Noel Paton (1900) has shown that there is not necessarily any difference in the 
nitrogenous metabolism of dogs before and after splenectomy. Frouin (1902) has 
demonstrated that the remoyal of the spleen from dogs with an isolated stomach 
does not interfere with their nutrition even during a meat diet. Further, Camus 
and Gley (1902), Bayliss and Starling (1903), and Hekma (1904) have shown that 
extracts of the spleen have no activating action. The influence of the spleen on 
pancreatic digestion is still open to debate. 
An activating principle more easy of demonstration is that discovered by 
Dr. N. P. Schepowalnikow (1898) in the succus entericus, or the juice of the small 
intestines. This juice, though possessing no proteolytic action itself, has the power 
of augmenting the activity of the pancreatic ferment, and especially of the proteo- 
lytic ferment—trypsin. Indeed, it was found that the succus entericus would convert 
an otherwise inactive pancreatic juice into an active jutce. To the ferment, since 
such the activating principle was found to be, Pawlow gave the name of enterokinase. 
Others haye corroborated Schepowalnikow’s work, and Delezenne (1902) found ente- 
rokinase not only in the duodenum, jejunum, and slightly in the ileum, but also 
wherever leucocytes abound. In other words, he claims that the activating principle 
is generated by the white blood corpuscle. 
From the size of the pancreas in the elasmobranchs we should expect this 
organ to play a large part in the work of digesting food. Krukenberg (1877), in his 
work on selachians, found that the pancreas of these fishes was secreting amylopsin, 
steapsin, and trypsin. Richet (1878), however, was unable to find trypsin. More 
recently Yung (1899), working on Squalus acanthias, found amylopsin and lipase, but 
only occasionally trypsin. Yung attempted to get the juice by a fistula, but had little 
success. His water glycerin extracts were only occasionally active. He found that 
extracts of the spleen aided the activation of the pancreas. Sellier (1902) found that 
the pancreas of several selachians studied by him does not of itself digest proteid, 
but must be activated by the juice of the spiral valve. 
To determine just what part the pancreas of selachians plays in digestion and 
what enzymes it secretes, my work comprised experiments as follows: 
1. Pancreatic fistulee were made to obtain pure pancreatic juice. 
2. Water glycerin extracts and sodium carbonate extracts were made to extract 
the zymogens or enzymes. 
3. Extracts of the pancreas were combined with bile, and with extracts of the 
duodenum, spiral valve, spleen, stomach, and rectal gland. 
4. The fresh pancreas was used to determine the presence of lipase. 
5. The content of the spiral valve was studied. 
