THE FROG’S YEAR 51 
their life began—that is, after the eggs at the 
moment of being laid were likewise fertilized. 
Peculiar half-finished little creatures the newly- 
hatched larvee are—mouthless, limbless, blind, 
covered with microscopic cilia, with just the be- 
ginnings of a first set of gills. They attach them- 
selves by a horseshoe-shaped cement-organ to water 
weed, and subsist for some time on a legacy of 
yolk. It is an often-told story how these newly- 
hatched larve develop into true tadpoles, with open 
mouth, gill-clefts, and a second set of gills; how 
the limbs bud out; how the lungs develop and the 
two-month-old pollywogs learn to use them, taking 
gulps of air at the surface; how the circulation 
changes from a piscine to an amphibian type; and 
show after nearly three months have passed there 
‘is a striking metamorphosis, the outcome of which 
isa tiny frog. The substance of the tail is broken 
up, and dissolved as if a pathological process had 
become normalized; the amceboid phagocytes which 
play such an important role in inflammation have 
their share in changing the tadpole into a frog, 
now acting as sappers and miners, and again as 
transporting agents. The mouth changes its char- 
acter entirely; the tongue, hitherto small, increases 
notably; the eyes, hitherto beneath the skin, reach 
the surface at last. It is time for the young frog to 
get ashore, else it will drown. It has been shown 
experimentally that not even the common water- 
frog can live under water for more than ten minutes, 
