ON CEREBRO-SPINAL LYMPH 69 



cells and fibres of the systemic nervous system are 

 dependent, and in which they " take root " and grow 

 grow as plants grow from the soil in which they have 

 been sown, or planted, and to follow out the comparison 

 much in the same manner as we observe in such plants 

 as those of the strawberry family, the primary cerebral 

 cell representing the original unit, seed, or plant, and the 



FIG. 3. TRANSVERSE SECTION THROUGH THE BRAIN AND SKULL MADE 

 WHILST FROZEN. (Key and Retzius. ) ^. 



, corpus callosum ; below its middle part the septum lucidum, and below that 

 again the fornix ; L K, lateral ventricle ; th t thalamus ; between the two thalami 

 the third ventricle is seen ; below the thalamus is the substantia innominata ; 

 sir, lenticular nucleus of the corpus striatum ; c, caudate nucleus of the same ; 

 between th and sir is the internal capsule ; outside str is the thin grey band of 

 the claustrum, and outside this again the island of Reil at the bottom of the 

 Sylvian fissure ; n. a. nucleus amygdalae ; immediately within this is the optic 

 tract seen in section ; /, pituitary body ; A', body of the sphenoid bone ; sa, 

 subarachnoid space ; v, villi of the arachnoid. 



various ganglionic cells, developed throughout the spinal 

 and other ganglionic centres, the secondary and semi- 

 independent group of plants related to the parent unit. 

 (Figs. 3, 8, 9, 10, n). 



Moreover, in the development and evolution of the 

 nervous system within the embryo, a process of neuronal 

 growth, somewhat akin, in its various stages, to the 

 progress of a creeping plant, may be said to take place, 

 which terminates only when the whole embryonic areas 



