526 Dynamic TJieory. 



We found in the study of fermentation, that plants possess the means 

 for the production of one or more digestive diastases or ferments. In 

 animals, the secretion of such ferments is performed by organs differ- 

 entiated and adapted to that end. But the plant appears to secrete 

 these ferments, in many cases, without the intervention of any distin- 

 guishable organs. There must be cells scattered through the tissues of 

 plants, which produce these diastasic elements. In animals, these cells 

 are organized into aggregations or organs. But in the insectivorous 

 plants, the glands, or some of them, are also thus organized, and of 

 several sorts, as it appears from the foregoing accounts. Thus, in these 

 plants there is a beginning of that reciprocity of offices between differ- 

 entiated parts, that is carried to such a great extent in animals. 



CHAPTER LY. 



ELECTRIC ORGANS. 



The Muscles and Glands discussed above, are organs in which one 

 mode of physical motion is turned into another ; viz. , Electricity into 

 Work. There is another class of organs in which electricity is accumu- 

 lated and not converted into work, nor silently discharged, as from or- 

 dinary muscles, as fast as formed, but in which it is accumulated under 

 powerful tensions, and liberated in violent shocks at the will of the an- 

 imal possessing the organs. These are called Electric Organs, and they 

 are good means of defense to the animals owning them. The principal 

 electric fishes are the electric ray ( Torpedo electrica and Torpedo mar- 

 morata ) of the Adriatic and Mediterranean, the Gymnotus electricus, or 

 electric eel, of the fresh waters of S. America, and the Malapterurus 

 electricus, or M. beninensis, from the bay of Benin on the west coast of 

 Africa. The electric organs of all these are essentially alike. ' ' They 



FIG. 251. Cross section of Malapte- 

 rurus Electricus, 

 A. Skin. 

 B. Electric Cells. 

 C. Cellular Tissue. 

 D. Nerve. 

 E. Artery. 

 F.-Vein. 



G. Adipose (non-conducting) tis- 

 H. Muscles. [sue. 



( Owen, from P acini.) 



consist of a large number of mi- 

 nute and delicate plates, which, 

 arranged side by side and en- 



FIG. 251?* closed in coverings of connective 



tissue, form the whole organ. In the Torpedo these organs lie flat on 

 either side of the vertebral column. In the Gymnotus and the Malap- 

 terurus they are arranged longitudinally ; and in the latter they form a 



