228 A Study of the Structural Unit of the Liver 
HistroricaL NOTE. 
In 1664 Wepfer described lobules in the liver of the pig, and two years 
later they were again described by Malpighi who gave them their name. 
Malpighi states that the livers of all vertebrates are conglomerate glands, 
being composed of lobules which in turn contain acini. For a long time 
after this the capital problem in the anatomy of the liver was the study 
of the structure of the lobules and their relation to one another. 
In 1733 Ferrein described these lobules as being composed of two sub- 
stances, brown and yellow (substantia fusca and substantia flava) which 
formed respectively its medullary and cortical portions. In general this 
description was accepted by anatomists, sometimes, however, with a re- 
versal of the arrangement of the colors in the medullary and cortical por- 
tions of the lobule.’ | 
In 1832 E. H. Weber showed that the two colors of the lobule are due 
to an unequal distribution of blood in it, and a year later Kiernan, in 
his classic paper, denied altogether that the lobule was composed of two 
substances as described by Ferrein. We owe to Kiernan our present 
conception of the lobules; he described their shape and relation to one 
another, the amount and character of tissue between them, and what is 
more, their relation to the vascular system ; he also introduced our present 
nomenclature. The defining line around a lobule was broken up into 
spaces and fissures, spatia interlobularia when three lobules came to- 
gether, and fissure interlobulares between each two adjoining lobules. 
The spaces and fissures, which were not always easy to demonstrate, were 
no doubt included by Ferrein in the cortical portion of the lobule. It 
is seen that Kiernan’s interlobular spaces and fissures form a network 
between the lobules, and for this reason Theile calls them the substantia 
reticularis, and the lobule proper the substantia granosa. It was also 
shown that the order of the reticular and granular substances are reversed 
in hepatic congestion; in it the brown reticulum encircles yellow gran- 
ules, pseudogranules, as Theile calls them. The yellow “ pseudolobules ” 
are tough and more consistent than the true brown lobules. 
Before the time of Kiernan the usual confusion of terms naturally arose. 
For instance, Autenrieth accepted Ferrein’s cortical and medullary por- 
tions of the lobule, only he reversed the order of their colors. Evidently 
he was describing “ pseudolobules.” Merkel, who also no doubt studied 
hyperemic livers, did the same. Krause took the “ happy mean ” course 
1See Kiernan, Phil. Trans., 1833; Theile, Handworterbuch der Physiologie, 
II, 1844; and Oppel, Lehrbuch der Vergleichenden Mikroskopichen Anatomie 
der Wirbelthiere, III, 1900. 
