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GEORGE ARNOLD. 
tional. The same holds good of the hypoblast, bat the 
meso-blastic cells show granules, chondriokonts occurring in 
them only occasionally. 
Meves also established the fact that up to the 3 days 
9 hours stage (beyond which stage his observations do not go) 
all the cells still contain chondriosomes, of which those in the 
neuroblasts have already (three days) begun to lose their 
mitochondrial staining reaction, and respond only to the 
specific staining reactions of neurofibrils. 
Hoven (1910) has studied the genesis of the neurofibrils of 
the chick in detail, and has shown that they are undoubtedly 
derived, as Meves had previously suggested, from the chon- 
driosomes, i.e. they are the products of the metamorphosed 
embryonic chondriosomes. 
In 1899 Benda put forward the view that the myofibrils 
were formed out of mitochondria, but it is to Duesberg (1910), 
that we owe conclusive proof of the nature of those structures. 
His work is entirely in support of Benda’s views, and shows 
that the myofibrils of striated muscle-fibres are the products 
of metamorphosed chondriosomes, being derived entirely from 
the chondriosomes of the embryonic muscle-cells. 
It will be beyond the limits of this paper to enter into the 
theories which have been put forward as to the role of the 
chondriosomes. Suffice to say, Meves (1911) has shown that 
in Ascaris, at least a part of the mitochondria of the male is 
carried by the spermatozoon into the egg and there fuses with 
the mitochondria of the female. 
From these and other facts Meves came to the conclusion, 
which is now widely held by those observers who have studied 
the chondriosomes, that those structures function, inter alia, 
as the cytoplasmic bearers of hereditary qualities just as the 
chromatin and linin are assumed to function in that role in 
regard to the nucleus. 
Also that in somatic tissues, the chondriosomes form the 
fundamental material from which are manufactured the sub- 
stances specific of the different tissues. Thus, he remarks : 
“ Mit der Sonderung des Embryonalleibs in verschiedene 
