122 ; Chronicles of Science. [Jan., 
most external and internal fibres are more or less longitudinal, and 
the deeper or more central fibres become more and more oblique as 
the centre of the parietes is reached. The longitudinal intersect 
the very oblique at nearly right angles; the slightly oblique and 
oblique at more acute angles. Dr. Pettigrew considers that there 
are indications of seven layers of fibres, three external, three in- 
ternal, and one intermediate ; but he uses the term layer in a more 
restricted sense than in his former papers on the heart and bladder, 
and now admits that there is a mutual interchange of fibres between 
the different layers. 
Minute Structure of the Liver.—New views with regard to this 
matter have lately come before the world, and seem to be very 
generally accepted by the leading histologists. Hering, Eberth, 
and other foreign observers, have renounced Dr. Beale’s view, as 
also that which attributes to the bile-ducts the formation of distinct 
capillaries within the lobules, having a membrana propria like the 
blood capillaries, and in contact only externally with the liver-cells. 
Professor Turner supports the new view, which is, that the bile 
passes to the periphery of the lobule in channels, which lie between 
and have their walls formed by the liver-cells, and which commu- 
nicate with the interlobular branches of the hepatic duct. Prepa- 
rations of rabbit’s liver, in which the bile-ducts have been injected 
immediately after the death of the animal, are the data which have 
lead to this new conception. Professor Hering has also studied 
the lives of many other mammals and reptiles. 
The Gall-Bladder.—The gall-bag is a most strangely variable 
organ. Dr. Macalister states that it is constantly present in bimana, 
quadrumana, cheiroptera, insectivora, carnivora, marsupialia, mono- 
tremata; absent from cetacea; variable in edentata, pachydermata, 
rodentia, and ruminantia. As a rule it is present in birds and rep- 
tiles, and almost universally in fish. An explanation of its varia- 
bility (varying sometimes even in the same species) is that it is 
required in those animals whose intervals of feeding are protracted, 
and is of little use in those in which the bile flows continuously from 
the liver, to aid in the almost constant process of digestion. 
The Axolotl and its Gill-tufts—It has been long thought that 
the Mexican perennibranchiate Salamander might prove to be 
merely a larval form, and develop into a true Salamandroid. More- 
over, the presence or absence of gills or their apertures in the adult 
state has been found to be merely a question of degree, and not of 
much taxonomical value. Van der Hoeven pointed out that the 
giant proteid of Japan could not be separated from the American 
Menopoma, though in the first the gill apertures are lost in adult 
life, and in the second they are persistent. From the experiments 
of M. Auguste Duméril on the Axolotls now alive and breeding in 
the ménagerie at Paris, it appears that in this creature the per- 
