866 DR. BH, KLEIN. 
like a network of homogeneous fine fibres, as described by 
other observers. 
Thus it is seen that the intervascular network of fine 
fibres first described by Billroth and accepted by Frey, Kol- 
liker, Schweigger-Seidel, Kyber, and others, as forming the 
matrix of the splenic pulp, seems, according to Miller, not 
to be a preformed structure as such, but to be rather produced 
by hardening reagents. The intercellular substance of Kyber, 
which is included in the intercellular substance of Miller, is 
different from this latter by being distinct from the inter- 
vascular network of fine fibrils. 
With regard to the relation of the pulp tissue to that of 
the Malpighian corpuscles and the adenoid sheath of the 
arteries Schweigger Seidel and W. Miiller, as well as Frey, 
maintain that both are identical; according to Billroth, how- 
ever, and Kyber, both these tissues show more or less marked 
differences. Kyber finds that the pathology of the spleen 
proves the pulp parenchyma and the lymphatic sheath 
to be two different tissues. 
Before I come to describe the results of my own investiga- 
tions into the structure of the parenchyma of the pulp of 
the spleen I must say a few words in respect to the methods 
I employed. I used the spleen of rat, cat, dog, monkey, and 
man. I may mention here thatthe pulp of the spleen of the rat 
and the cat is similar to that of the dog, whereas that of the 
monkey is similar to that of man. For the investigation of the 
dog’s spleen I use the following method :—Through the com- 
mon trunk of the splenic artery of a freshly killed animal, 
(after ligaturing the small branchlets given offto the omentum) 
4 per cent. solution of common salt is injected into the spleen 
under gradually increasing pressure (from 60 to 160 mm. 
Hg.), until the fluid running out by the splenic vein appears 
perfectly clear and not to contain (for the unaided eye) any 
more blood, the whole spleen having become by that time 
swollen and pale, as is especially well seen on its edges. 
After this ; per cent. osmic acid is injected for about 
twenty to thirty minutes, beginning with 60 mm. pressure, 
and increasing it to 180 mm. ‘The spleen is then placed, as 
a whole, in Miiller’s fluid. After eight to twelve days small 
bits are cut out, placed in alcohol for several hours, and used 
for preparing sections, which are stained and mounted in 
the ordinary way. ‘Lhe spleen of man is prepared in this 
way :—As soon as possible after death small bits are placed 
in a large excess of } per cent. chromic acid, which is re- 
placed by } per cent., after six to eight days. After a few 
