Chap. VI.] DIGESTION. 71 



CHAPTER VI. 



THE DIGESTIVE POWER OF THE SECRETION OF DROSERA. 



The secretion rendered acid by the direct and indirect excitement of the 

 glands Nature of the acid Digestible substances Albumen, it8 di- 

 gestion arrested by alkalies, recommences by the addition of an acid 

 Meat Fibrin Syntonin Areolar tissue Cartilage Fibro-cartilage 

 Bone Enamel and dentine Phosphate of lime Fibrous basis of 

 bone Gelatine Chondrin Milk, casein and cheese Gluten Legu- 

 min Pollen Globulin Usematin Indigestible substances Epider- 

 mic productions Fibro-elastic tissue Mucin Pepsin Urea Chitine 

 Cellulose Gun-cotton Chlorophyll Fat and oil Stareh Action 

 of the secretion on living seeds Summary and concluding remarks. 



As we have seen that nitrogenous fluids act very differ- 

 ently on the leaves of Drosera from non-nitrogenous fluids, 

 and as the leaves remain clasped for a much longer time 

 over various organic bodies than over inorganic bodies, such 

 as bits of glass, cinder, wood, &c., it becomes an interesting 

 inquiry, whether they can only absorb matters already in 

 solution, or render it soluble, that is, have the power of di- 

 gestion. We shall immediately see that they certainly have 

 this power, and that they act on albuminous compounds in 

 exactly the same manner as does the gastric juice of mam- 

 mals; the digested matter being afterwards absorbed. This 

 fact, which will be clearly proved, is a wonderful one in the 

 physiology of plants. I must here state that I have been 

 aided throughout all my later experiments by many valuable 

 suggestions and assistance given me with the greatest kind- 

 ness by Dr. Burdon Sanderson. 



It may be well to premise for the sake of any reader who 

 knows nothing about the digestion of albuminous compounds 

 by animals that this is effected by means of a ferment, pep- 

 sin, together with weak hydrochloric acid, though almost 

 any acid will serve. Yet neither pepsin nor an acid by itself 

 has any such power.* We have seen that when the glands of 



* It appears, however, accord- though slowly, a very minute 



Ing to Scbiff, and contrary to the quantity of coagulated albumen. 



o|>inion of- 8oroe physiologists, Schlff, ' I'hvs. do la Digestion,' 



that weak hydrochloric dissolves, 18C7, torn. li. p. 25. 



