1905.] Distribution of Chlorides in Nerve Cells and Fibres. 191 



chlorides of nerve fibre, just as in ordinary egg-albumen, must be contained. 

 Such a distribution of electrolytes would not permit the ions carrying the 

 electrical charge to travel unimpeded and, in consequence, the change of 

 potential transmitted would progress with greatly diminished velocity. This 

 diminution would bring into line as parallel, if not very like, phenomena, the 

 nerve impulse and the electrical current. 



It may be freely admitted that one has not all the data necessary to 

 establish certainty on this point, and that caution should be shown in 

 drawing conclusions where so much is still unknown. Tbe facts, however, 

 stand out prominently. The occurrence of electrolytes, in the form of 

 •chloride or chlorides, in a concentrated degree, uniformly distributed in and 

 along the course of the axon ; the maintenance of this concentration through 

 the impermeability of the medullary sheath and the neurilemma ; the high 

 •conductivity of the axon ; the occurrence of electrical phenomena on injury 

 of the axon ; these and other facts relating to the physical properties of 

 nerve fibres justify one in proposing an explanation. 



EXPLANATION OF PLATES. 



Figs. 1 — 9 are from silver nitrate preparations of nerve fibres, figs. 10 — 19 represent 

 the action of mercurous nitrate on the same, while figs. 20 — 26 illustrate the action of the 

 silver nitrate solution on capillary tubes filled with albumen or gelatine. 



Plate 2. 



Fig. 1. — a and b from the sciatic of the frog, c from the sciatic of the guinea-pig. 

 AgN0 3 ^ + 1-5 per cent. HN0 3 , 24 hours, x 1000. 

 N 



Fig. 2. — Sciatic fibres, frog. AgN0 3 — + 1'5 per cent. HN0 3 , 24 hours, thoroughly 



washed, then placed in 5 per cent. CaCl 2 solution : a for 2 hours, b for 

 8 hours, x 590. 



N ' 

 Fig. 3. — Sciatic frog. AgN0 3 — + 1*5 per cent. HN0 3 , 24 hours, 5 per cent. NaN0 3 



solution, 30 hours, a is the situation of a node of Eanvier. x 590. 



rom spin 



b x 670. 



Fig. 5.— From spinal cord of frog. AgN0 3 ^ + 1-5 per cent. HN0 3 . x 2000. 



Fig. 6. — a from spinal cord, b and c from sciatic nerve of frog, a and b illustrate the 



N 



division of strise. AgN0 3 ^ + 10 per cent. HN0 3 . x 3000. 



Fig. 7. — From spinal cord of guinea-pig, illustrating both the diffuse and the striated 



N 



(laminated) distribution of the chlorides of the axon. AgN0 3 — + 1" per 



cent. HN0 3 , 24 hours, x 1000. 

 Fig. 8. — From sciatic of rat, representing the distribution of the chlorides sometimes 



N 



found after treatment with AgN0 3 — + 10 per cent. HN0 3 . x 590. 



N 



Fig. 4. — From spinal cord of frog. AgN0 3 — + 1*5 per cent. HN0 3 . a x 3000, 



