744 FEED C. KOCH 



increase in tlie number of white and red corpuscles in the blood in rabbits. 

 Thus, 0.01 gram of a dried acid extract per kilo bodyweight after fifty 

 minutes caused an increase of 44.2 per cent in the white corpuscles and 

 17.07 per cent in the erythrocytes, and this persisted for an hour or more. 

 They also noted that rabbits, previously starved for forty-eight hours and 

 then fed cabbage water and oats, showed an average increase of 76.7 per 

 cent in the white corpuscles and 18.65 per cent in the erythrocytes with 

 the maximum effect 3.2 and 1.9 hours after the meal. Lambert and 

 Meyer (1902) find secretin to act almost equally well on salivary and 

 pancreatic secretions. Piticariu reports the increased flow of urine as a 

 result of duodenal secretin preparations. It is, of course, possible that 

 some of these other physiological effects may be due to impurities in the 

 secretin solutions, but until this is proven to be the case these facts should 

 be borne in mind. In the discussion under peristaltic hormone, it will be 

 seen that possibly one and the same substance may be causing both secre- 

 tion and peristalsis. 



A few in vitro studies suggest a specific affinity on the part of the 

 pancreas tissue for secretin. Thus, Hkmill and Dixon (1908-9) find that 

 the secretin activity can be destroyed by incubating solutions thereof 

 with various tissues, but that in this respect the pancreas is so very much 

 more active than other tissues that it can almost be considered a specific? 

 action. They found that a definite amount of pancreas tissue is capable 

 of destroying only a definite amount of secretin. Liver tissue also 

 appeared to have a specific affinity for the secretin, but in this case the 

 secretin activity could be recovered by extraction of the mixture; in 

 other words, the secretin did not appear to be destroyed in this case. 

 Hamill and Dixon considered that the secretin converts a prozymogen 

 form of the enzymes into a zymogen form, and that it is destroyed in 

 this process just as epinephrin is destroyed when it acts physiologically. 

 The authors also observed that the flow of pancreatic juice, brought about 

 by the intravenous administration of secretin, could be arrested by an 

 injection of pancreatic emulsion, especially if the latter was injected be- 

 fore the injection of the secretin. Lalou (1912) in part confirmed these 

 observations. Delezenne and Pozerski (1904-1912) report that a 0.9 

 per cent sodium chlorid solution is very efficient in extracting secretin 

 from duodenal mucous membrane, providing it is boiled immediately after 

 the extraction. They conclude from their studies that if such extracts are 

 not heated the secretin is rapidly destroyed by the proteolytic enzymes 

 present in such an extract ; and that the reason a 0.4 per cent hydrochloric 

 acid solution is a good extraction medium is because it inhibits the action 

 of these proteolytic enzymes. It is barely possible that the supposed 

 destructive action observed by others in pancreatic tissue may be due to 

 the same factor. Hamill and Dixon observed that boiled pancreas extracts 

 do not possess the destructive action and that secretin aids the entero- 



