586 William Patten 



seeu to be strongly varicose, so that, with a lower magnifying power, 

 the same granular effect is produced, while, with the strengest immer- 

 sion lens, Y20 Leitz, the connection between the varicosities may be 

 distinguished. In the most perfect examples, the fibrillae are in the 

 majority of cases smooth. Another and better proof that the structures 

 in question are real fibrillae, proceeding from the axial nerve, may be 

 obtained in the following manner. By treatment, for 18 hours, in chromic 

 acid, V4 or VsVo» ^ peciiliar effect is produced, for, upon sections of 

 such material, or by teasing in dilute chromic acid, it will appear as 

 though the rods were destroyed, or at least so badly distorted and broken, 

 as to lose all trace of their former shape. The fact is, however, that 

 the rods bave burst, the inner ends broken off, and the coutents been 

 forced out, or left hanging in various positions. The ragged sheaths 

 of the rods are usually left attached to the ends of the retinophorae. It 

 is the nervous cores of the rods which interest us most, and many of 

 them may be found as ovai, or egg-shaped masses, with one end drawn 

 out into a coarse fibre, either perfectly free, or showing ali stages of de- 

 tachment from the rods; there can be, therefore, no doubt of their origin. 

 On closer inspection, it will be seen that the fibrous Prolongation, which 

 is the detached, axial nerve, is continued into the centre of the mass, 

 and there gives rise to lateral branches, which on the periphery be- 

 come continuous with irregulär, circular ones. The relation, which these 

 three series of fibres bear to those of the axial core, is so evident as to 

 be beyond question and furnishes a proof that the nervous structure, 

 attributed to the rods, really exists and is not produced by the coagu- 

 lation of the rod substance. In osmic acid, the rods are stained a deep 

 blue, or black, not due to any fatty substance contained in them, as is 

 shown by their determined resistance to ali fat solvents, but to the 

 innumerable nerve fibrillae, with which the entire rod is permeated. 

 Hensen first saw the axial nerve fibre in the retinophorae, and was able 

 to follow it a short di stance into the celi. His remarks lead one to be- 

 lieve that it was a disagreeable duty to record his observations, on ac- 

 count of the difficulty of bringing them into agreement with his remar- 

 kable theory upon the connection between sense cells and nerve fibres ! 

 Carrière (19), also, saw what was probably the axial nerve, but did 

 not consider it as such because, in focusing, it moved back and forth 

 (p. 106)! 



Finally, a word in regard to the nuclei of the retinophorae. No one 

 was able to determine, among the confusion of nuclei, which of them 

 belonged to the retinophorae. Hensen does not mention the subject in 



