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directions. The question promises^ besides^ not to be settled 

 so quickly, for we see M. Grandry describing recently, both 

 in the cylinders of the axis and in the nervous cells them- 

 selves, certain transverse strise that can be rendered very dis- 

 tinct by the action of nitrate of silver. There would appear 

 to be here a regular alternation of two sorts of discs, different 

 both by their refractive properties and by their chemical 

 characters. As M. Grandry does not deny the longitudinal 

 character of the fibrillse, he is obliged to admit for the nerves 

 a structure very like that of the muscular fibrillse. 



The ganglion-cells are, then, veritable knots of fibrils. In- 

 voluntarily one asks oneself with ]M. Arndt if this structure 

 can be reconciled with the function that is ordinarily attri- 

 buted to these organs. Until now these cells have passed for 

 the central points of all nervous irritation, for the centres 

 which give birth to all nervous phenomena. The discove- 

 ries of which we have just rendered account no longer permit 

 us to regard them as aught else but the points of concentration 

 of irritations coming in different directions, destined, perhaps, 

 to transmit them to other spots. In the actual state of science 

 the purely fibrillar and granular substance of the cortical layer 

 of the cerebrum, and without doubt of all grey substance, 

 ought, it seems, to be considered as a tissue essentially irri- 

 table. The irritations of this tissue are transmitted by the 

 fibrils to the ganglion-cells, which, after having concentrated 

 them, transmit them to the cylinders of the axis to which 

 they give birth. It is thus, at least, that things should 

 happen in response to centrifugal excitation of nervous acti- 

 vity. But it is clear that the movement ought to take place 

 in an inverse direction for centripetal irritations. These irri- 

 tations, accumulated in the various cells, are distributed by 

 the prolongations of these bodies to the fibrillar and finely 

 granular matter of the grey substance. This matter, it ap- 

 pears, ought to play henceforward an important part in phy- 

 siological theories, and it is urgent to give it a naine. That 

 of "'terminal fibrillar network," proposed by M. Stephany, 

 is perhaps the best. Although placed in the nervous centre, 

 this network is truly terminal in this sense, that all the 

 nervous elements finish by terminating there. 



Without doubt we must not diminish too much the im- 

 portance of ganglion-cells, but it must be agreed that it has, 

 perhaps, been exaggerated. In the first days that follow 

 birth there does not exist in the brain any nerv^ous fibre nor 

 any ganglion- cell, but only elements of the fibrillary and 

 granular terminal substance with its nuclei, and yet there is 

 already at this time transmission of orders from the centre 



