286 On the Connection of Nerves and Chromohlasts. 



which draws them with it in its different movements. But it 

 sometimes happens that the finest expansions in turning upon them- 

 selves leave these granulations in the midst of the smTOunding 

 tissues. 



Our observations, made to investigate the relation between the 

 nerves and the chromohlasts, have been carried out upon the pectoral 

 fin of young flat-fish, about 4 centimetres long. The organ taken 

 fi.-om the living fish is treated with dilute acetic acid, about 1 to 1^ 

 per cent. ; then very slightly tinted with carmine. The preparation 

 thus made has been examined with an object-glass of 10 mm., of 

 Nachet, which admits of one seeing through the whole thickness of 

 the fin. In all cases it is treated with chloride of gold, feebly 

 acidulated with acetic acid ; it was placed under this reagent after 

 having been in acetic acid a sufiicient length of time to admit of the 

 detachment of the epidermis. 



The only elements of a connective nature that I have seen are 

 nuclei, surrounded by a greater or lesser quantity of a hyaline sub- 

 stance, which appears resistant, and affects a bi-polar disposition 

 of the two extremities of the great axis of the nucleus. These cells 

 without a trace of apparent membrane nevertheless differ much ; 

 in fact, as much in relation of form as in that of size of the nucleus 

 as well as the polar substance. 



Fig. 2, Plate CVIII., represents exactly one region of the inter- 

 posed membrane with two rays. The nuclei affect a distinctly 

 parallel relation; they are narrow with regard to their length. 

 The polar substance is there, and recalls the appearance of the 

 fusiform todies of the superior vertebrae. In other instances the 

 same elements show themselves disposed in a quite different man- 

 ner. They are at the same time more voluminous, more closely 

 related, and they affect a parallel disposition. Their position is 

 then ordinarily perpendicular to that of the rays. In some parts 

 it is not rare to see a certain number of these elements affect a 

 definite (determinee) direction, whilst others have a perpendicular 

 direction. 



The nuclei of those contiguous conjunctive cells, as shown in 

 Fig. 1, vary considerably in volume, hke the elements themselves, 

 almost from the single to the triple. They assume in preparations 

 treated as we have du-ected, an ovoid form, and seem to exhibit in 

 their interior the trace of a voluminous spherical nucleolus. The 

 diameter of the nucleus may be estimated on an average at 6 — 7" ; 

 its volume is always proportional to the quantity of polar substance. 

 Two nuclei are sometimes seen in these fusiform bodies, which seem 

 to prove that they multiply by fission. We have represented an 

 example, and also some aberrant forms in Fig. 1. 



Capillaries are rare, and are sometimes , accompanied by a thin 

 nervous thread, Fig. 4. The latter is recognizable by narrow 



