GANGLIA. 



cxliii 



Dr. Beale's observations have been made chiefly on the ganglia of frogs, the cells of 

 which have very commonly a pyriform shape like the one represented in the figure. 

 In mammalia they are more spheroidal, and the observation of their connection with 

 fibres is more difficult; but from examinations in mammalia, so far as they have gone, 

 Dr. Beale infers that the relation of the cells and fibres is essentially the same as in 

 frogs. 



Fig. LXXXII. 



Fig. LXXXI1I. 



Fig. LXXXII. GANGLION-CELL OP A FROG, MAGNIFIED; ACCORDING TO BEALE. 

 Reduced and adapted from one of his figures, a, a, straight fibre ; b, b, coiled fibre ; 

 C, smaller one joining it. 



Fig. LXXXIII. MAGNIFIED GANGLION-CELL, PROM THE SYMPATHETIC OF THE FROG, 

 ACCORDING TO J. ARNOLD. Virch. Arch. 1865. 



a, straight fibre ; b, coiled fibre, arising by a superficial net connected with nucleolus 

 of the cell ; c, c, capsule with nuclei. 



Two subsequent writers, Julius Arnold, and L. G. Courvoisier, have confirmed 

 Dr. Beale's original observation in almost every point ; but whilst Beale describes 

 the two fibres as connected with the substance of the cell and at its surface only or, 

 at least, could not obtain satisfactory evidence of its passing into the interior 

 Arnold, and (after him) Courvoisier describe (has had previously been done by Har- 

 less and others) the straight fibre as traceable into the nucleus, with which Arnold 

 thinks its medullary sheath, here altogether inconsiderable, is continuous, whilst the 

 axial part ends in the nucleolus, which he regards as the knobbed end of the axis- 

 cylinder. They both describe a network of exquisitely fine fibrils, which, springing 

 from the nucleolus as a centre, traverses the substance of the celt and comes to the 

 surface between the celt-body and its sheath, and finally unites into the spiral fibre. 

 According to this account, the nucleolus is, as it were, the end of the straight fibre and 

 beginning of the spiral one, or vice versa ; or, at least, the point of organic connection 

 between them in the cell. 



