444 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The unusual size and the forms of the nuclei, and especially the 
presence of figures of direct nuclear development, together with the 
presence of several nuclei in one cell, are all characters which have been 
noted in cells which have an intense secretory or assimilating function ; 
the peculiarity of the present case is the arrangement of the chromatin. 
In the absence of any knowledge of similar cases it is difficult to suggest 
what this means. One is inclined to regard the chromatic centres of the 
star-figures as themselves nucleoli, around which the chromatin has, from 
some cause, become radially arranged. It has long been known that a 
large number of nucleoli may be found in gland-cells, and, indeed, in 
some other kinds of cells too. It is possible that the phenomenon has 
something to do with multipolar indirect cell-division ; we might 
imagine that each centre was a centrosoma, and regard the division of the 
centres as divisions of centrosomata ; but to this supposition it is easy to 
raise objections, and, at present, the best way of finding an explanation 
is to multiply examples of this peculiar mode of arrangement. 
Micrometric Study of Red Blood-corpuscles.* — Prof. M. D. Ewell 
has made an elaborate micrometric study of blood, which is one of the 
few methods of identifying that fluid which is -worthy of discussion. No 
reliance can, however, be placed on the micrometric test unless the 
errors of the micrometer used, with reference to some authentic standard, 
are known. When the subject continues during a short period in 
substantially the same condition of good health, there appears in the 
hands of the same observer to be an average size of the fresh corpuscles, 
provided at least one hundred are measured. As several tables given by 
the author show, there are such large discrepancies between the averages 
obtained from the measurement of the fresh blood-corpuscles of animals 
of the same species, and between measurements of the same objects by 
different observers, as to throw doubt on published results. There is no 
advantage in using very high powers in these investigations. The 
drying of blood-corpuscles in a clot multiplies the difficulty of identifi- 
cation ; it has never been proved that dried corpuscles can be restored 
to their normal proportions. The mean size of the red corpuscles of 
very young animals is larger, and their size varies between wider limits 
than in adults. Many diseases alter the size of the red corpuscles, and 
fasting and various drugs diminish both their size and number. It is 
impossible, therefore, in the present state of science to say more of a 
given specimen of blood, fresh or dry, than that it is the blood of a 
mammal. 
Histology of Central Nervous System. f— Prof. A. Kolliker, in his 
first communication on this subject, deals with the minute structure of the 
cerebellum. He finds that the granular layer contains a few glia-cells, 
and a large number of multipolar nerve-cells — the small and large 
granular cells. The former are very numerous, and have short proto- 
plasmic processes, which divide at the end into small tufts. The very 
fine nervous process generally arises from a protoplasmic process, passes 
into the molecular layer, and then divides into two horizontal and longi- 
tudinal unbranched fibrils, the termination of which is unknown. There 
* North Amer. Practitioner, ii. (1890) pp. 99-107, 173-86. 
f Zeitschr. f. Wiss. Zool., xlix. (1890) pp. 663-89 (4 pis.). 
