378 
DR. LIONEL BEALE ON THE 
So also it is only in the liver of the pig that a prolongation of the areolar tissue 
can be demonstrated between the ultimate portions of secreting structure. 
In the human liver areolar tissue is abundant in the large portal canals, but it 
gradually diminishes in quantity as the branches of the vessels become smaller, and 
their most minute ramifications are entirely free from it, as Bowman, Henle, and 
Vogel have previously observed. In the liver of the seal it is very sparing in quan- 
tity in the portal canals, but in some of the rodent animals it seems to be reduced to 
a minimum (rabbit, rat, mouse). In the rabbit a very little areolar tissue is found 
even in the largest portal canals. 
In subjecting sections of uninjected specimens to examination, the smallest branches 
of the vessels are inevitably stretched and torn by manipulation, and thus a striated 
appearance, closely resembling that of fibrous tissue, is produced. 
As is well known, the vessels of the kidney and of other glands at their point of 
entrance, are invested with a covering of areolar tissue, which is gradually lost as 
they divide into smaller branches in the glands. A similar arrangement occurs in 
the case of the liver, but from the large size of the gland this investment is prolonged 
for a considerable distance into its interior. 
Method of j)reparmg Specimens. 
In consequence of the softness of the liver, I have been unable to demonstrate the 
arrangement of the minute ducts and their connexion with the cell-containing net- 
woi'k without previous hardening. This hardening may be effected in several different 
ways. By soaking small pieces of liver in strong syrup for several weeks, they become 
so firm, that very thin sections can be readily obtained. The liver may also be hard- 
ened in alcohol, and afterwards rendered transparent by soda. I have also succeeded 
in obtaining good sections from pieces which had been soaked in the mixture of 
alcohol and acetic acid, recommended by Mr. L. Clarke in investigating the struc- 
ture of the cord. The fluid, however, which has afforded the most satisfactory 
results, consists of alcohol, to which a few drops of solution of soda have been added. 
In this mixture the liver becomes perfectly firm and transparent at the same time*. 
In my investigations I have employed several other solutions, but the above are 
most worthy of notice. Some of the livers were hardened in the state usually ob- 
tained from dead animals, others were partially injected from the duct in order to 
force the bile into the smaller ducts before they were hardened, and in some instances 
the bile duct was tied some hours before the death of the animal. 
* The advantage of this solution seems to depend upon the opposite action of the two fluids. The alcohol 
precipitates albuminous compounds, and renders them hard and opake. The soda, on the other hand, softens 
and dissolves them, rendering them transparent. In conjunction, these operate in rendering the tissue quite 
hard and transparent at the same time. I am still prosecuting experiments with this fluid. Large preparations 
have been preserved in the alkaline fluid with advantage. I have succeeded in making some most beautiful 
preparations, showing the ossification of the bones in the embryo at different periods in this manner. 
