THE EEL. 333 



surface." The scale of the eel in nearly every case presents evidence of 

 this. 



The barbs of this fish, like those of the carp, appear to be endowed with 

 nerves of touch possessing the most exquisite power of feeling. In the 

 tail, also, there is a network of blood vessels, which Yarrell has figured 

 in his book, calling the appearance a " lymphatic heart." Apropos of 

 this, it is only necessary to give a violent blow to the tail in order to kill 

 the eel. This is one of two ways. The other and surest is to separate 

 the brain from the spine by cutting immediately below that part which 

 corresponds to the cerebellum of the human being. 



In connection with this lymphatic heart, it may be here not out of 

 place to give such particulars of this exceptional physiological phe- 

 nomenon as I have been able to gather. In the " Naturalist's Library," 

 edited by Sir W. Jardine, the following comprehensive details of such 

 organs are given : 



" In all living beings, besides the very necessary process of the 

 ingestion and absorption of aliment, it is now very generally understood 

 that there is a directly contrary, or, at all events, a very distinct opera- 

 tion going forward, whereby the effete matter of the system is unceasingly 

 withdrawn and discharged from the body by a process which is designated 

 'absorption' and 'interstitial absorption,' and which is unremittingly 

 operating in every part and tissue of the living frame. In invertebrate 

 animals this function is discharged by the same machinery which moves the 

 blood, whilst in the vertebrate an additional system is brought into play, 

 known under the name of the ' lymphatic.' In fishes this system is exhi- 

 bited in its simplest and most diffused form, these vessels being extensively 

 distributed through the superficial and deep-seated parts of the body ; 

 they are also extremely distensible, and have no valves, as in the higher 

 animals. In reptiles, although the general character of the system is 

 much the same, yet the following peculiarity has recently been discovered 

 by Professor Muller, namely, that pulsating dilatations of the lymphatic 

 trunks very generally exist, and it is to these he has given the name of 

 lymphatic hearts. The Berlin professor first discovered them in the 

 frog, and subsequently in toads, salamanders, and lizards. In the first- 

 named animal there are two pairs, one situate in the neck, subservient 

 to the upper extremities, and the other, near the hip joint, to the lower. 

 These hist are placed immediately under the skin, and can be readily 

 seen acting in the living animal, pouring their limpid contents into some 

 continuous vein. Neither are they synchronous with each other on the 

 two sides of the body, nor always performed in the same space of time ; 

 they are often irregular, and exhibit long and frequent intermissions. 

 When in regular action they contract about ninety times in a minute. 



