206 
J. BEARD. 
his latest statements on the development of nerves, and find 
(No. 50, p. 9) that he quotes with approval Balfour’s views. 
He says, “ Balfour showed that, contrary to the generally 
accepted theory, the nerves are outgrowths from the 
central nervous system, and therefore of epiblastic origin, 
instead of being, as formerly supposed, structures arising 
independently in the mesoblast and only acquiring a secondary 
connection with the brain and cord.” Ilensen (No. 25), 
Kolliker (No. 43, p. 621), Sagemelil (No. 56, p. 33), van 
Wijhe (Nos. 60, p. 18), Bedot (No. 9, p. 186), Shipley (No. 
58), Beraneck (Nos. 10, 11), and Misses Johnson and Sheldon 
(No. 38), have practically accepted Balfour’s and Marshall’s 
views; and van Wijhe (No. 61, p. 4) has used the conclusion 
as an argument against my views of the epiblastic origin of 
the sensory nerves of the branchial sense organs (Beard, No. 6, 
p. 69). He remarks, “Wenn Beard jetzt, seiner friikeren 
Behauptung entgegen, den Olfactorius und die Seitennerveu 
nebst ihren Ganglien alleiu aus der Epidermis enstehen lasst, 
so kann er dies wohl nei beweisen weil der Stamm der Nerven 
sich urspriinglick aus dem Medullarrolire entwickelt.” 
It is not difficult from the researches I have here recorded — 
and others as yet unpublished — to conclude that all these 
authors have been mistaken in describing the ganglia as out- 
growths of the central nervous system. The figures I have 
given demonstrate the justice of this criticism, and as a final 
argument, which more especially negatives Balfour’s remark 
(quoted earlier), that the neural crest clearly belongs to the 
brain, I will point out that the limits of the two structures, 
brain and ganglionic Anlagen, are very early sharply separated 
off by a well-defined line (figs. 45, 51, 32 — 36 and others), and 
only in those stages in which the neural plate is quite open, in 
fact only during the primitive-streak period can one really, with 
any pretence to accuracy, speak of a common Anlage for both 
structures, of an encephalo-gangliouic Anlage. But this is a 
stage at which the embryo is barely differentiated into the 
three embryonic layers. 
Onodi (No. 51) has shown the true source of origin of 
