DR. MARTIN RARRY ON FIBRE. 115 



less obvious : but I noticed in the same situations minute threads of a spiral form, 

 and am inclined to think that they were the nuclei in an altered state. 



110. It is gratifying to me to find in the observations of Dr. REMAK -f- a confirma- 

 tion of one previously communicated to the Royal Society by myself (and realizing 

 an idea of Professor OWEN), viz. the reproduction of the blood-corpuscles by means 

 of parent cells J. 



111. Farther, the observations of REMAK led him to believe that the blood-corpus- 

 cles of the foetal chick of the third week are propagated by " division." I must here 

 add, that division of the nucleus is what I have been long indicating as the mode of 

 reproduction, not only of blood-corpuscles, but of all other cells. 



112. It remains to be seen whether my further observation also, that the parent 

 cells are altered red blood-discs, will not be confirmed. 



1 13. According to Dr. HANNOVER, the pale central fibre or primitive band has no 

 concern in producing the varicosities of nervous fibre: and from the observations of 

 Dr. REMAK, it appears that the pale sheath takes no part therein ; but that it is the 

 opaque sheath ("white substance") that becomes varicose^. This accords with my 

 view (par. 39), that the varicosities result from a rupture in many parts, and a re- 

 coiling, of the remarkable filaments of which (according to my observations) the 

 "white substance" is composed ||. 



1 14. Since the foregoing memoir was presented to the Society, I have seen the re- 

 markable filaments therein described (par. 6) in " false membrane," in the horny 

 tissue of the hoof, in the chorion and amuion of one of the Mammalia, and in the 

 chalazoe of the Bird's egg. The latter consisted entirely of them. 



115. It has long appeared to me questionable, whether the generally received opi- 

 nion is correct, that the chalazre consist merely of coagulated albumen to which a 

 spiral form has been given by revolutions of the ovum in its passage through the ovi- 



t British and Foreign Medical Review, January, 1842, p. 229. From the Medicinische Zeitung, Juli 7, 1841. 



J My paper, recording the above observation, was read January 14, 1841. See Philosophical Transactions, 

 1841, Part II. p. 201. figs. 39, 41 y, 45 x, 53 ft. MULLKR'S Archiv, 1841, p. 512. 



[| A friend has pointed out to me a figure by FONTAKA, which I am glad to have the opportunity of noticing 

 while the paper is going through the press. It shows, I think, that this observer, sixty years since, discerned 

 traces of the filaments of which I find the " white substance" to be composed. He describes a primitive ner- 

 vous cylinder as appearing to have " 9a et la sur les parois quelques fragmens de fils tortueux." (Traite' sur 

 le V6nin dc la Vipere, Tab. IV. fig. 1. p. 279.) 



Another friend has pointed out to me in a recent work by VALENTIN, that has just come into his hands 

 (SAMUEL THOMAS VON SOMMERRING, Hirn-und Nervenlehre), a passage which, so far as it goes, agrees with an 

 observation recorded in the foregoing memoir, namely, the formation of membrane out of spiral fibres (pars. 

 42, 55). VALENTIN states that, under favourable circumstances, it is possible to discern that the delicate mem. 

 brane surrounding the contents of the nerves is formed of fibres ; two of which he describes as appearing to 

 run screw-like around the tube. L. c,, p. 5, 8. 



Q2 



