GELATINOUS NEKVE-FIBRES. 25 



this system connected with involuntary movements. For 

 instance, these fibres are very abundant in the gray filaments 

 sent to parts provided with non-striated muscular fibres and 

 endowed with undoubted motor properties ; but they are not 

 found in the white filaments of the sympathetic, which seem 

 to be incapable of exciting movements. 1 



There is considerable difference of opinion among physi- 

 ologists with regard to the gelatinous filaments. Some are 

 disposed to regard them as elements of connective tissue, not 

 endowed with properties characteristic of nerves, while others 

 consider that they are nerve-fibres, probably possessing func- 

 tions distinct from those of the fibres of different structure. 

 The first opinion was formerly held by Kolliker, who states, 

 in one of the early editions of his work on Microscopic 

 Anatomy, that all of the fibres of Remak are " only a form 

 of connective tissue ; " 3 but in a later edition, he admits that 

 the nucleated fibres of the great sympathetic, which resemble 

 embryonic nervous elements, are really nerve-fibres. 8 This 

 is the view now adopted by the best anatomists. While it 

 is certain that elements of connective tissue exist in the 

 nerves, and have been mistaken for true nerve-fibres, there 

 are in the nerves, particularly in those belonging to the 

 great sympathetic system, fibres exactly resembling the 

 nerve-fibres of the embryon. These are the true gelatinous 

 nerve-fibres, or fibres of Remak. It is stated that the nerves 

 generally have this structure up to the fifth month of intra- 

 uterine life, and that in the regeneration of nerves after 

 division or injury, the new elements assume this form before 

 they arrive at their full development. 4 



The true gelatinous nerve-fibres present the following 

 characters: They are flattened, with regular and sharp 

 borders, grayish and pale, presenting numerous very fine 



1 REMAK, Observation&s de Sysfematis S"erv. Struct., Berolini, 1838, p. 5. 



2 KOLLIKER, Microscopic Anatomy, London, 1860, p. 254. 



8 KOLLIKER, Cements d"histologie humaine, Paris, 1868, p. 432. 



4 LITTRE ET ROBIN, Dictionnaire de medecine, Paris, 1865, Article, Nerveux. 



