Connective Substances. By T. E. Sattertliwaite. 241 
determined by such researches as Dr. Eichardson has so well 
undertaken ; and surely even this attempt, whatever may be the 
ultimate result, is so praiseworthy as to deserve cordial assistance. 
Photographs, according to his practice, will be quite essential 
in this kind of evidence. And those prepared by him, and by 
Dr. Mees and Professor Wormley, may be accepted as very favour- 
able examples of American micrography. I have yet seen no 
others of the same kind. Whether they have been followed in 
England or elsewhere I know not. 
VI. — On the Structure and Development of Connective Substances* 
By Thomas E. Satterthwaite, M.D., Microscopist to St. Luke's 
Hospital (N.Y., U.S.A.). 
Plates CLIX. and CLX. 
(^Continued from page 199.) 
4. Neuroglia, or Bind-web, Seguin (Fig. 7, Plate CLIX.). — But 
a short time since it was not known positively whether the delicate 
cementing substance of the nervous system, but more especially of 
the brain, was granular or fibrous. Even after Yirchow claimed 
that this substance was like the other tissues known as connective, 
doubt was still thrown upon the matter, for the defining power 
of the objectives then used was often insufficient to make out these 
delicate objects. At the present time the actual existence of such 
a dehcate network is hardly called in question, for it may be de- 
monstrated with really good glasses, such as some of the immersion 
lenses (No. 10) of Hartnack's system. As to the question of the 
corpuscular elements there is, even now, some question, and it can 
hardly be regarded that their exact form and shape have been 
definitely agreed upon by histologists. We find, it is true, that, 
where there is considerable development of connective material 
along the central canal of the spinal cord, there we have the 
ordinary fibres and corpuscles already described, and so, too, near 
the surface of the convolutions. When, however, we examine the 
supporting substance of the white and grey masses, it is more 
doubtful as to the character of the delicate tissue we meet with. 
The real condition may be tolerably well seen by adopting the fol- 
lowing plan. Place any portions of the brain or cord in a weak 
solution of bichromate of potash (5 per cent.) or Miiller's fluid for a 
few days, and then immerse it in alcohol until hard, and make thin 
* Through an omission on the part of the engraver— during the Editor's 
absence — the figures were not placed on the plates in the first part of Dr. Satter- 
thwaite's paper. Hence the accompanying plan is now supplied, by means of 
which the reader will be enabled to refer to tlie plates without difliculty. 
s 2 
