The Ouiuiiouus Glands of Comiiiou Toads. 353 



To test the effects following gland discharge, I selected six toads 

 for an experiment. The left parotid gland of each was stimulated 

 with electricity, till apparently exhausted of its milky secretion. 

 Viewed externally, the elevation of the stimulated wart was greatly 

 reduced in every case. The right parotid was in no case stimulated, 

 and remained unaffected. The toads were killed at different intervals 

 and both the right and left glands were sectioned. No. 1 was killed 

 immediately, No. 2 in 6 hours. No. 3 in 12 hours. No. 4 in 30 

 hours. No. 5 in 52 hours, and No. 6 in one week from the time 

 of stimulation. The right glands in every case appeared normal. 

 With the exception of a few sacs in the left glands of Nos. 1 and 

 6, the large sacs of all the individuals were completely empty. The 

 few filled sacs do not seem to have discharged at all. In every case, 

 many of the emptied glands had completely collapsed, and, in most 

 instances, all of the sacs had collapsed. It is evident from sections of 

 a given pair of parotids that they were before the emptying of the 

 left very much alike in the shape, arrangement and development of 

 the different batteries of glands. After the stimulation the smaller 

 glands, i. c, those of the outer battery, had remained intact as far 

 as their shape and epithelium were concerned. The small mature 

 glands had emptied. 



It is certain that emptied gland sacs have not refilled with secre- 

 tion seven days after emptying. Further than this I do not wish to 

 draw definite conclusions from this experiment, since only one indi- 

 vidual was killed at each interval. It is, however, my belief that a 

 collapsed gland sac, one that had lost its shape, never refills. Fur- 

 ther, that a completely emptied gland that has not collapsed at first 

 will ultimately do so, from the force of surrounding growth and 

 pressure. 



According to Bristol and Bartelmez, poison glands are found 

 only on the upper surface of the toad, and mucus glands over the 

 whole surface. ""HATien the poison is discharged, the remains of the 

 gland are resorbed, and at the same time one of the five or six un- 

 developed glands, grouped about the mouth of the functioning gland, 

 grows down alongside the remains of the discharged gland pushing 

 it aside to occupy its former place." The authors make no statement 

 as to the nature of these replacing glands other than the above. 



