Literary Notices. xi 



and for varying time (four-fifths Miiller's fluid and one-fifth osmic acid i 

 per cent, for one to two days, followed by three-fourths per cent, nitrate 

 of silver), l 



The proportions of bichromate of potash and osmic acid may vary 

 considerably. In some cases it is preferable to place the tissues directly into 

 a mixture of 4 parts 3 per cent, bichromate and i part i per cent, osmic 

 acid, though what little experience we have had favors the previous 

 partial hardening in 3 per cent, bichromate of potash. 



It IS unnecessary to recapitulate the results given -in Van Gehuchten's 

 paper already alluded to, for they constitute, in the main, a repetition of 

 the facts summarized in the first volume from Prof. Kolliker's papers in 

 the Zeitschrift f. wissensch. Zoologie. 



The point of greatest theoretical interest connected with the recent 

 applications of Golgi's method is the light thrown on the problem of the 

 transferrence of nervous excitement. Instead of direct translation of nerve 

 stimuli through continuous paths we are to conceive of a radiation or 

 induction through a more or less resisting or impervious medium. Instead 

 of nervous continuity, we have at most nerve contact or propinquity as a 

 condition of discharge. Thus a distinct physical basis is afforded for the 

 resistence theory of reflex action. Plate XI, Fig. i, from VanGehuchten, 

 illustrates the conditions for voluntary motion. The impulse generated 

 in a cortical cell (a) passes via the axis-cylinder process by either a direct 

 or crossed tract in the cord to the vicinity of one of the radical cells of the 

 ventral cornu with which it is more or less closely connected by means of 

 so-called collaterals. A single cortex cell may be associated with a num- 

 ber of the motor cells of the cord. Simple reflex action is explained by 

 Fig. 2 A, in which (a) is the sensory root giving ofCcollaterals which divide 

 into minute fibrils about the motor cells of the anterior cornu. In other 

 cases, by means of the fibres of the ascending columns and their collaterals 

 the excitement is carried for a greater or less distance cephalad, finding 

 exit through the motor collaterals in regions above that excited. Fig. 2, 

 B. Still again, the collaterals of the excited fibre, by contact with 

 numerous commissural cells, transfer the excitement to the ventral cornu 

 of the opposite side. Fig. 2, C. 



Fig. 3 is a diagram intended to illustrate the relations in the cere- 



1. Romeo FusARi, Intorno alia fina anatomia dell' eucefalo del Teleostei. Atti 

 della R. Ace. del Lencei cl. fis. ecc.,4a, Vol. IV. 



