Monthy Microscon'| Histology of Minute Blood-vessels. 207 
arriving at certainty with regard to the facts on which our future 
theories of inflammation are to rest. 
Most of the preparations here referred to are examples of the 
results attainable by staining the tissues with a dilute solution of 
the nitrate of silver. This reagent has been employed for various 
histological purposes during the last ten years, and has attracted 
attention especially in connection with the cornea, the various forms 
of connective tissue, the ultimate branches of the lymphatics and the 
boundaries of the cells which constitute epithelial surfaces. General 
attention was first drawn to its use by Dr. F. von Recklinghausen, 
of Berlin, in 1860,* and further particulars were contributed during 
1861, by Prof. His, of Basel,t who would appear to have already 
employed the reagent for several years. In 1862 Von Reckling- 
hausen published his work on the lymphatics,{ which contains a 
detailed account of many elaborate experiments with regard to the 
action of silver solutions on the tissues, and in 1863 Dr. Ernst 
Oedmanson, of Stockholm,§ gave a description of their behaviour 
when applied to epithelial surfaces, and described and figured the 
so-called stomata which play so important a part in the theory of 
Cohnheim. During 1865 and 1866 the epithelium of the capillary 
blood-vessels, as shown by silver, was described by several observers, 
among whom Dr. N. Chrzonszczewsky, of Charkow,|| may be par- 
ticularly mentioned. 
The perusal of these papers led me to make a number of experi- 
ments myself, and to have others made by my assistants at the 
Museum, the results of which are now to be described. 
If a dilute solution of nitrate of silver is brushed over a clean 
epithelial surface taken from a recently killed animal, and the tissue 
after washing with distilled water is exposed for a short time to the 
action of sunlight, it will be found on microscopical examination that 
a brownish black precipitate of silver has been produced at the 
boundaries of the epithelial cells, while the cells themselves are com- 
paratively but little stained, or if the manipulation has been care- 
* “Wine Methode, mikroskopische hohle and solide Gebilde von einander zu 
unterscheiden,” Virchow’s ‘ Archiv,’ Bd. XIX., 8. 451. 
+ ‘Ueber das Verhalten des Salpetersauren Silberoxyds zu thierischen 
Gewebsbestandtheilen,” ibid., Bd. XX., S. 207. 
t ‘Die Lymphgefiasse und ihre Beziehung zum Bindegewebe,’ Berlin, 1862. 
§ “Beitrag zur Lehre von dem Epithel,’ Virchow’s ‘ Archiy,’ Bd. XXVIIL., 
S. 361. 
|| “* Ueber die feinere Structur der Blutcapillaren,” ibid., Bd. XXXYV., 8. 169. 
C. J. Eberth, in his article on the blood-vessels in Stricker’s Handbook (*‘ Hand- 
buch der Lehre von den Geweben, &c.’? Leipsic, 1869. II. Lief: S. 202) enu- 
merates the following microscopists as having described the epithelium of the 
capillaries prior to Chrzonszezewsky :—Hoyer, ‘ Archiv fiir Anatomie,’ Jan. 18, 
1865. Auerbach, ‘Breslauer Zeitung, Feb. 17, 1865. Eberth, ‘ Sitzungsberichte 
der physikal. med. Gesellschaft zu Wiirzburg,’ Feb. 18, 1865; ‘ Medicinisches 
Centralblatt,’ No. 13, 1865; ‘ Wiirzburger Naturwissenschaftliche Zeitschrift, 
Bd. VI., 1866. Aeby, ‘ Medicinisches Centralblatt,’ No. 14, 1865. 
