CHAP. VI. DIGESTION. 119 



and butyric acids, and it was completely dissolved by 

 these fluids at the ordinary temperature of a room. 

 Here, then, at last, we have a case in which it appears 

 that there exists an essential difference in digestive 

 power between the secretion of Drosera and gastric 

 juice ; the difference being confined to the ferment, 

 for, as we have just seen, pepsin in combination with 

 acids of the acetic series acts perfectly on gluten. 

 I believe that the explanation lies simply in the fact 

 that gluten is too powerful a stimulant (like raw 

 meat, or phosphate of lime, or even too large a piece 

 of albumen), and that it injures or kills the glands 

 before they have had time to pour forth a sufficient 

 supply of the proper secretion. That some matter is 

 absorbed from the gluten, we have clear evidence in 

 the length of time during which the tentacles remain 

 inflected, and in the greatly changed colour of the 

 glands. 



At the suggestion of Dr. Sanderson, some gluten 

 was left for 15 hrs. in weak hydrochloric acid (-02 per 

 cent.), in order to remove the starch. It became 

 colourless, more transparent, and swollen. Small 

 portions were washed and placed on five leaves, which 

 were soon closely inflected, but to my surprise re- 

 expanded completely in 48 hrs. A mere vestige of 

 gluten was left on two of the leaves, and not a vestige 

 on the other three. The viscid and acid secretion, 

 which remained on the discs of the three latter 

 leaves, was scraped off and examined by my son 

 under a high power ; but nothing could be seen 

 except a little dirt, and a good many starch grains 

 which had not been dissolved by the hydrochloric 

 acid. Some of the glands were rather pale. We 

 thus learn that gluten, treated with weak hydro- 

 chloric acid, is not so powerful or so enduring a 



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