62 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Spiral Fold of Selachian Intestine.* — Dr. Paul Mayer has an in- 
teresting note on this subject. Jeffery Parker spoke of that of Baja as 
■“ tbe most remarkable case on record of spontaneous variation,” and 
distinguished four types. But Mayer shows that these are in part 
artefacts and in part functional changes due to the amount of food and 
the state of digestion. 
Classification of Monstrosities.! — M. Louis Blanc distinguishes : — 
(n) those abnormalities which arise from an ovum with one nucleus ; 
(6) those which arise from an ovum with two nuclei ; (c) those which 
arise from an ovum with multiple nuclei. He also distinguishes 
the abnormalities (a) of formation (defect, excess, or malformation) ; 
(&) of development (defect, excess, or some other perturbation) ; and 
(c) of growth (defect or excess). The detailed classification follows 
the different systems of the body. 
b. Histology. 
Precis of Histology.^ — Prof. M. Duval has published & precis of his 
course of lectures on histology, an up-to-date and carefully thought out 
introduction to the subject, which is sure to be valued throughout the 
wide circle of histologists. 
Sickle-shaped Nuclei and Giant-Spheres in Resting Epithelial 
Cells. § — Prof. E. Ballowitz describes these in the pharyngeal and cloacal 
cavities of Salpa ; each nucleus has an exquisite sickle-shape, and some- 
times the ends meet ; each concavity contains a very large sphere with 
radiate structure and two or three centrosomes. 
Energids of Plants and Animals. || — Prof. A. von Kolliker sums up 
the general result of a detailed comparison, as follows. In the organisa- 
tion of plants naked energids play no part, being replaced by those 
which are surrounded by a cellulose membrane and have become true 
cells. Yet the conditions of growth and organisation of the energids 
determine the forms of the cells and organs. Cuticular structures and 
intercellular substances take little part in the construction of the plant, 
and functional alloplasmatic products of energids are almost wanting. 
In animals, on the other hand, naked energids play a very essential 
part in the formation of many organs, prominent among which are epi- 
dermic structures and glands. Moreover the energids produce abundant 
intercellular substances, connective tissue, elastic tissue, dentine, carti- 
lage, and bone. Especially characteristic of animals is the fact that 
functional alloplasmatic energid-products, especially muscle-cells and 
nerve-cells, attain dominance, rule the whole life, and form the typical 
animal organs. 
Number of Chromosomes in Somatic Cells of Man.f — Prof. W. 
Flemming points out that this has never been estimated with certainty. 
Hansemann gives numbers from 18 to 40 ; Bardeleben in dealing with 
spermatogenesis mentions 8 and 16. From preparations of the corneal 
* MT. Zool. Stat. Neapel, xii. (1897) pp. 749-54 (1 pi.). 
f Journ, Anat. Physiol., xxxiii|(1897) pp. 100-4. 
X 1 Precis d’Histologie,’ 8vo, Paris, 1897, xxxii. and 956 pp., 408 figs. 
§ Anat. Anzeig., xiii. (1897) pp. 602-4. 
H Yerh. Phys.-Med. Ges. Wurzburg, xsxi. (1897) pp. 202-21. 
1 Anat. Anzeig , xiv. (1897) up. 171-4 (1 fig.). 
