290 
GEOEGE AENOLD. 
In the meantime Firket’s observations just published have 
provided that evidence which makes the probability a 
certainty. 
Firket based his researches on sections of the “ egg-tooth ” 
(le diamant) of the chick. This corneous organ, which lies on 
the tip of the beak and drops off shortly after hatching, 
enables the chick to break through the shell. 
It arises originally from two layers of ectodermal cells, and 
by proliferation of the latter eventually forms a horny conical 
knob on the upper mandible. When fully formed it consists 
of many layers of cells, which may be divided into three zones, 
viz. the basal layer, and the inferior and superior mucous 
layers. 
In sections of the egg-tootli from a three days old embryo, 
Firket ascertained that all the cells of the basal zone con- 
tained chondriokonts. These are confined to the cytoplasm 
of each cell and do not pass from one cell to another. The 
superior mucous zone, i.e. the outermost, contains typical 
epidermal fibrils, but the cells of the intermediate zone, the 
inferior mucous, contain both chondriokonts and fibrils, the 
latter increasing in proportion as the cells approach the 
superior zone. Every stage between chondriokonts, charac- 
terised by being confined within the limits of each individual 
cell, and true fibrils, passing from one cell to another, is to 
be seen, so that ee Les transitions entre fibril les et chondrio- 
somes sont d’ailleurs presque insensibles.” 
The importance of correlating the epidermal fibrils with 
the embryonic chondriosomes lies in the relation of the latter 
to Altmann’s granula, in view of the assertion made by some 
observers that Altmann’s grauula are absent from the cells of 
malignant growths. 
The researches of Meves and Samsonnow (1910) have 
demonstrated decisively that the chondriosomes are identical 
with the granules of Altmann, where the latter are not 
artifacts, and certainly under that category must be classed 
not a few of the different granules described by Altmann. 
What seems to be granules by Altmann’s method appear as 
