THE FKESII-WATER AQUARIUM. 83 



where we may observe, just behind tho eyes, a round 

 opening, through which the water is forced ; but, though 

 lie is furnished, like fish, with gills, they seem to be imper- 

 fect, for sometimes he must come to the surface to breathe, 

 and does so in a strange wriggling manner, somewhat like 

 an eel. Though the " tads " are herbivorous, they will eat 

 animal matter, and, indeed, even their own kindred. After 

 a time, the creature increases in size, the hinder part of 

 the body swells, and at last, the budding of the hind legs, 

 which are always the first to appear, may be distinctly 

 seen. When these are perfect the other pair make their 

 appearance in the same way, though sometimes I have 

 observed that if the " tad" is carried any distance and 

 roughly treated, the hind and also the fore legs will often 

 spring through the skin in one night, aud then we have 

 a curious lizard-like animal. As soon as he has got his 

 legs, the gills disappear, and the tail gradually dwindles 

 away, its substance going to build up the body. When 

 this is gone, we must take care, or our frog will also be 

 gone, as he now fancies the land as much as the water, 

 and will crawl up the corner of the tank and so make 

 his escape, unless we cover it, a good way of doing 

 which is to stretch a piece of gauze on a frame and lay 

 it over the top. The poor frog seems to have been 

 created for the experiments of the philosopher, for it is 

 he that has to take all the new poisons, that we may 

 observe their effects ; it is he that has to suffer what Dr. 

 Hall terms "Strychnizm ;"" it is he that serves as a gal- 

 vanic battery, and it is in his leg or tongue that the cir- 

 culation of the blood is exhibited under the microscope to 



