Royal Microscopical Society. 9 



In the sympathetic ganglionic bodies, finally, we may compare 

 the hodij, enclosed within the capsule, to a ganglionic body of the 

 cortical layer of the cerebrum, while the co/jsw/e itself — representing 

 a fine fibrillous network, the meshes of which are filled with small 

 granules — is analogous to the terminal network in the granular 

 substance. From the body, enclosing its nucleus as all other 

 ganglionic bodies, we observe some processes arise, which, after 

 having pierced the capsule, give rise to axis cylinders which are 

 finally transformed into dark-bordered nerve fibres, while the ramifi- 

 cations of a number of smaller processes, also arising from the body, 

 terminate in the network of the capsule. From the outer surface 

 of the latter, lastly, a number of fine fibrillae arise, a part of which 

 establish a communication with the adjoining capsules, while the 

 rest unite to form the ultimate sympathetic nerve fibres, going to 

 the periphery. 



5. The Nerve Fibres and Ganglionic Bodies of Insects. — Tlie 

 nerve fibres of insects consist of fine granular fibrillse, about 

 yoVo iiiDi. in diameter, enclosed within a structureless sheath, and 

 thus representing the entire ner\'e. In the nerve fibre of an insect, 

 therefore, we behold the conducting anatomical element of the nervous 

 tissues in its primitive form, that is, as a simple axis-cylinder fibre. 

 The history of the development of these tissues in the human embryo 

 justifies this view. The fibrillse running parallel to each other in 

 the sheath of the nerve are not divided into subordinate bundles. 

 They are surrounded by a semi-liquid substance, resembling in 

 character the nerve-medulla of the dark-bordered nerve fibre of the 

 higher animals. 



The ganglionic bodies of insects are round or slightly oval 

 bodies, from each of which a large process, composed of fine fibrill^e, 

 arises. They consist of a mass of granules, surrounding a large, 

 clear nucleus. The latter, about j-^ mm. in diameter, shows a 

 fine double contour, and contains a greenish shining nucleolus of 

 2^0 mm., composed of several granules. From the sm-face of the 

 granular mass surrounding the nucleus a great number of tine short 

 fibrillae arise, which slightly anastomose with each other. From 

 these anastomoses others arise, the greater portion of which join in 

 forming the large process, while the rest pass over to the adjoining 

 ganglionic bodies to establish a reciprocal communication. A sheath, 

 enclosing the whole body, seems not to exist. The ganglionic 

 bodies of a ganglion are, like those of the sympathetic nervous 

 system of the higher animals, divided into groujjs. The processes 

 arising from the bodies of a group, unite to form nerve-fibre bundles, 

 and these, again, unite with those of other groups, forming still 

 larger bundles, from which, finally, the larger nervous trunks, 

 leaving the ganglion, arise. The whole ganglion itself is sur- 



