746 FEED C. KOCH 



* 



distinctly and furthermore that they never obtained an active secretagogue 

 free from depressor action. Many have assumed that the absolute alcohol 

 extraction, as applied by Bayliss and Starling, is efficient in removing 

 the vasodilatin action without actually proving it to themselves. Certainly 

 absolute alcohol extraction is not efficient in making a clear cut separation 

 of gastrin from vasodilatin activity, and probably the same is true for 

 secretin and vasodilatin. Hamill and Dixon laid considerable stress on 

 preparing their extract free from vasodilatin, but they do not publish data 

 showing the extent to which this was done. Dale and Laidlaw (1912) 

 employed an entirely different method by means of which they claim to 

 have obtained a product which a has a powerful secretin action and is 

 relatively free from depressor substance." They could precipitate their 

 substance by picric acid. Their work was reported in a very brief article, 

 and no further confirmatory evidence from them has come to the notice 

 of the writer. Launoy and Oechslin (1013) report that by repeated re- 

 precipitation with absolute alcohol they obtained a very active prepara- 

 tion, and a blood pressure tracing taken therewith shows it to be free from 

 depressor action, but with good secretagogue action as a result of the 

 same dose. They apparently obtained a vasodilatin free secretin prepara- 

 tion. Their description of the method employed is, however, so brief that 

 it will be very difficult to confirm their findings. A further study by them 

 led them to the conclusion that a difficultly soluble picrolonat mixture 

 may be obtained. From this mixture they obtained three fractions, one 

 consisting of red octahedral crystals melting at 262 C., another con- 

 sisting of needles a similar to histamin picrolonate melting above 300 C.," 

 and a third fraction, very active as a depressor substance and possessing 

 some secretagogue activity, but not as active as "other extracts or de- 

 pressants." As stated before, some of the older observers considered it 

 probable that secretin is nothing other than cholin and that cholin is 

 Popielski's vasodilatin. Vcn Fiirth and Schwarz (1908) concluded that 

 cholin is present in the Bayliss and Starling secretin preparation, but 

 that only a part of the secretagogue action therein is due to cholin. Le 

 Heux (1918), on the other hand, finds that extracts from the intestinal 

 mucosa contain sufficient cholin to account, in a measure, for the peris- 

 talsis stimulating power upon the intestinal musculature. As previously 

 stated, under the discussion of the specific distribution of secretin, Uhl- 

 mann (1918) takes practically the same view as Popielski as to the 

 general action of secretin, only he takes a still broader view as to the 

 site of action and distribution. He considers the antineuritic vitamin to 

 be such a substance. Jansen, however, claims to have shown that this 

 vitamin and secretin are not identical. 



The preponderance of evidence certainly is in favor of the view that 

 secretin is not the same as gastrin, histamin or cholin, but we are by no 

 means certain that it is not a depressor or vasodilatin. 



