558 A. B. DAWSON 
D. Regeneration 
1. Of granular glands. a. In other Amphibia. There is con- 
siderable diversity of opinion regarding the fate of the discharged 
glands, but it is almost uniformly admitted that the cells of the 
granular glands pass bodily into the secretion mass and that the 
expulsion of the secretion involves the death of the cells. How- 
ever, Weiss (’99) and Nordenskidld (’05) believe that, in the 
toad, the gland cells are not completely transformed into secre- 
tion and are, therefore, not destroyed, but that the protoplasm 
of the inner part of the cells furnishes new secretion and again 
fills the emptied sac. Calmels (’83) and Seeck (’91) describe 
replacing cells within the old glands, but, according to Muhse 
(09) and others, they mistook cross-sections of smooth muscle 
fibers for young epithelial cells. Schultz (’89) states that the 
cells of the poison glands multiply: by mitotic division and that 
only a few cells reach full development at the same time. 
According to Engelmann (’72), Junius (’96), and Muhse (’09), 
the emptied glands degenerate and new glands are developed by 
the embryonic method. In many Amphibia, however, definite 
processes of replacement of the exhausted epithelium have been 
described. Production of secretion is, therefore, in some Am- 
phibia maintained by a rehabilitation of the old gland, and not ° 
always, as Junius (’96) and Muhse (’09) claim, by the develop- 
ment of entirely new glands. In Triton, Nicoglu (’93) and 
Heidenhain (’93 a) find that inside the old poison gland there is 
present a second smaller gland possessing a lumen. ‘This small 
sac lies between the musculature and epithelium of the large 
gland, and when the latter is emptied of its secretion, the bud 
enlarges and occupies the old lumen. The place of origin of the — 
replacing gland is found by Heidenhain and Nicoglu to be in 
the small flattened cells immediately below the intercalary 
region. But Vollmer (’93), who also worked on Triton, concludes 
that the “Mutterboden der Driisenknospe das Keimlager das 
Rete Malpighi ist.”’ 
Talke (’00) believes that in all Amphibia regeneration is a con- 
tinuous process and takes place by mitotic division in the gland 
a 
