254? NUTRITION. 



as they were, " vim elusit, vegetusque evasit," as an illustration of this. Less 

 violent injuries are recovered from with far less danger and inconvenience than 

 we experience. The lower we descend into the scale, the greater tolerance of 

 violence and the greater powers of reparation and renewal do we observe. When 

 a salamander's head has been cut off, the wound has healed. (Dr. Edwards 

 1. c. p. 11.) If the head of a planaria from our ponds is divided longitudi- 

 nally a certain way, the wound heals : if completely, other new matter will be 

 deposited and join the two heads into one of great size, with one or two addi- 

 tional eyes ; or each half will become a new head. If the whole body is divided, 

 except at the tail, Siamese twins are made, which pull discordantly and tear 

 asunder their bond of union, and become independent. Not only does a 

 planaria acquire a new head after decapitation, but, if the two heads which have 

 been produced by division are removed, others have sprung up three times in 

 succession, and, the animal being then divided throughout and its head cut off, 

 one head only was now produced. If the animal is divided across, the anterior 

 half swims off, and even sends forth a tail : the tail sinks, but after a few days 

 sends forth a head. If cut across into three, the anterior and posterior proceed 

 thus, and the middle part shoots forth both a head and tail. Nay a planaria has 

 been cut into ten pieces, and each has become a perfect animal. (Dr. Johnson, 

 London Medical Gazette, Feb. 10. 1832.) Some mites live in alcohol, and flies 

 have come to London in a pipe of Madeira and revived. I have soaked a 

 caterpillar in Scheele's prussic acid, and seen it recover in half an hour. If the 

 polype, which is a gelatinous tube, with one end closed and the other fringed 

 for the purpose of receiving food and conveying it, is divided, the two halves 

 change at one end, the one closing, the other acquiring fringes, so that both halves 

 become perfect animals ; or, if a polype is inverted, the outer surface forms a 

 digesting cavity. 



Vegetables endure extreme violence. A log of mulberry-tree has sent forth 

 shoots on being placed in the ground as a post, after many years of neglect ; a 

 gooseberry-bush will grow if planted with its branches in the earth and its roots 

 in the air. 



