OBSERVATIONS ON STRUCTURE OF CELLS AND NUCLEI. 319 



In the present paper I propose to show by a simple method 

 and on an object easily attainable at all seasons of the year 

 that tlie statements of Professor Flemming, of Kiel^ above 

 quoted, as rej^ards the delicate network of fibrils more or less 

 uniformly pervadinj^ the interior of the nucleus of various 

 cells is in all respects perfectly correct. In addition to this 

 I shall have to notice several observations I made with 

 reference to the structure of the cell-substance itself and the 

 relation of it to the intranuclear network. 



A The stomach of a freshly killed newt [Triton cristatus) 

 is cut open and placed into a 5 per cent, solution of chromate 

 of ammonia in a closed vessel — (a reagent now well known 

 through the investigations of Heidenhain^ on the rod-like 

 structures in the epithelium of some of the urinary tubules, 

 and afterwards used by MacCarthy" for the demonstration of 

 the rods in the medullary sheath of nerve-fibrils) — where it is 

 kept for about twenty-four hours. It is then washed in 

 water for about half an hour and placed after this in a dilute 

 solution of picro-carmine, where it is left till it assumes a 

 deep pinkish-yellow tint. It is now washed in water, and 

 microscopic specimens are prepared in this manner : — The 

 mucous surface of the organ is scraped with a small scalpel, 

 whereby smaller or larger flakes may be easily removed ; they 

 are placed in a very tiny droplet of glycerine on a glass slide ; 

 by slight knocking with the rounded or flat top of any thin 

 rod or needle holder these flakes are broken up into micro- 

 scopic fragments ; a drop of glycerine is placed on a covering- 

 glass, and this is inverted over the above specimen. 



Examined under a moderately high power — say Hartnack's 

 7 or 8, or Zeiss's D or E — we recognise easily innumerable 

 isolated or groups of epithelial cells, and a great many 

 isolated nuclei or fragments of nuclei. If the scalpel has 

 been drawn over the surface of the raucous membraiic with 

 a little energy, the preparation contains great numbers of 

 gland-cells, isolated and in continuous masses, and also other 

 elements belonging to the tissue of the mucosa. 



1. What arrests the attention of the observer at once is the 

 striking appearance presented by all nuclei, everij one of them 

 shoioing cm extremely beautiful network of [fibrils, which per- 

 meates its interior uniformly. In some instances this network, 

 which we will designate ' intranuclear nettoork' does not 

 extend quite up to the nuclear membrane, which in all 

 instances is well defined, but leaves a narrower or broader 



' ' Archiv f. Mikrosk. Anatom./Bd. x, 1873. 

 - This Journal, 1875, p. 377. 



