ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
45 
He first emphasises his conviction that all cells have a protective 
limiting membrane. This conclusion rests partly on observation, partly 
on general physiological grounds. Centrosomes occur in resting cells, 
but Heidenhain’s “ primary centrodesmoses ” are regarded as mythical. 
The author finds no evidence of centrosomes budding, and he refuses to 
accept Heidenhain’s conclusion that every centrosome comes from a 
centrosome. 
Niessing has studied the plasmic fibrils which radiate out from the 
centrosome through the cell, some to the periphery, some ending freely, 
and some probably on the nuclear membrane. In this connection he 
runs a tilt against Heidenhain’s “ Spannungsgesetz .” He regards the 
centrosome as a body forming the centre or insertion of the protoplasmic 
fibrils. Against Heidenhain, again, he regards the astrosphere as more 
than a mere region ; it is a fibrillar system with special material (per- 
haps “ archoplasm ”) in the interfilar spaces. 
Fat-formation and Altmann’s Granules.* — Dr. A. Ccsaris-Demel 
has investigated the rapid appearance of fat in the epithelium of injured 
or diseased kidneys, and the supposed relation of Altmann’s granules to 
the fat-formation. The appearance of fat in the cells is interpreted as 
the result of diminished oxidation, following artificial lesion, ligature of 
the renal artery, choleraic infection, &c. The absence of intermediate 
forms, the localisation of the granules, and other facts point to the 
absolute independence of the fat-globules and the f'uchsinophilous 
granules of Altmann. 
Enamel-Structure "and Phylogeny.f — Herr G. Preiswerk notes how 
the families of Eodents are characterised by peculiarities of enamel- 
structure (Tomes), and how light has been cast on the relationships of 
Selachians by a study of the same tissue (Jrnckel). He applies this 
method to the extinct Ungulates. All fossil and living Ungulates which 
show a contour-band and a bow-shaped arrangement of the prism-sections 
of the diazonia are highly differentiated, while contour-striae and pave- 
ment-like prism arrangement of the diazonia point to enamel in process 
of differentiation. In man there are contour-striae, and the zonia show 
possibilities of further differentiation ; his teeth at least have not reached 
the goal. But it is difficult to follow a paper of this sort without figures. 
y. General. 
Iron Compounds in Animal and Vegetable Cells.J — Dr. A. B. 
Macallum has an essay on the distribution of assimilated iron compounds, 
other than haemoglobin and haematins, in animal and vegetable cells. 
After some preliminary remarks he gives an account of general observa- 
tions on the distribution of assimilated iron in highly specialised animal 
and vegetable cells. He next discusses the occurrence of assimilated 
iron in special forms of life, such as Protozoa, Fungi, Bacteria, Ascaris , 
and the larvae of Chironomus. The facts described appear to indicate 
that a substance in which iron is firmly held is a constant constituent of 
the nucleus or of the cytoplasm of non-nucleated organisms, and of those 
* Atti R. Accad. Sci. Torino, xxx. (1895) pp. 765-79. 
t Verh. Anat. Gres., ix., in Anat. Anzeig. Erganzungsheft, x. (1895) pp. 227-31. 
X Quart. Journ.<Micr. Sci., xxxviii. (1895) pp. 175-274 (3 pis.). 
