62 Journal of Comp.^rative Neurology. 



ules of the protoplasm are more loosely arranged than in an or- 

 dinary cell ; or the body in the centre might be regarded as a 

 cell, surrounded by a mass of granules for reinforcing or extend- 

 ing its nervous energy. In Miigil cepJialus these bodies occupy 

 the whole of the nucleus rotundus ; but in Crenilabnis there is a 

 space left in the center occupied only by granules and a network 

 of fibres [tract of coramissura horizontalis ! (H.)] In Crenilabnis 

 the circumference of this body is bounded by a layer of small 

 cells . . . which are elongate in shape and have a circular 

 nucleus, which contains several granules instead of a single nu- 

 cleolus. This nucleus often projects from one end of the cell, 

 giving to the latter a high-shouldered appearance ; the side of the 

 cell opposite its nucleus ends in one or two processes and is 

 always turned toward the centre of the nucleus rotundus. These 

 cells absorb coloring matter to a greater extent than most 

 others." 



Passing now to the structure of the nidulus ruber, which 

 has hitherto baffled all observers, we are fortunately able to re- 

 duce everything to simple elements and familiar combinations. 

 The examination with a moderate power (i -5th objective) pre- 

 sents the appearance so frequently described of gelatinous 

 masses, diffusely stained and of granular consistency scattered 

 in the meshes of a neuroglia net, which also ab )unds in spheri- 

 cal granules. Nevertheless this appearance is entirely illusory. 

 With immersion lenses our sections reveal a definite structure. 

 The neuroglia ground substance seems to be no m jre highly dif- 

 ferentiated than in many other parts of the brain, but it is supple- 

 mented by a vast number of nerve fibres which, being chiefly 

 nonmedullated, give a dense appearance to the mass. Blood- 

 vessels are perhaps more numerous than in any other part of the 

 brain and form a complete minute capillary reticulum, which in 

 itself is evidence of tremendous vital activity of some kind. 

 The most striking nervous elements are large multii)olar ganglion 

 cells which resemble those of the medullary part of the hypoiria 

 (substantia nigra). These cells give off two or more large axis- 

 cylinder processes, besides a number of small protoplasmic pro- 

 cesses, which are soon lost in the substance of the nidulus about 

 the blood-vessels. To these cells the same interpretation may 

 be given as to the similar cells of the nigra and many other re- 



