Monthly Microscopical 
vournal, July Lio, | PROGRESS OF MICROSCOPICAL SCIENCE. 43 
It was then observed (by means of such appliances) that the aber- 
ration developed by high-power eye-pieces and a lengthened tube, 
followed a peculiar law. 
Passage of Pigment Cells through the Capillaries—Some very curious 
observations on this subject have recently been made by Signor Savi- 
otti, of Turin, and have been recorded in the ‘ Lancet’ of May 28th. 
Dr. Saviotti being engaged in studying the inflammatory process in 
the web of the foot of the frog, first obtained a circumscribed spot of 
inflammation by means of a drop of collodion, and after a few days 
found the pigment cells of the irritated spot accumulated around the 
vessels in a contracted condition, and in the course of a short time that 
they had entirely disappeared. He immediately applied himself to 
the question of explaining the mode of their disappearance. In other 
frogs he excited inflammation by dropping on the web a small quantity 
of a 2 per cent. solution of sulphuric acid. Again, after a few days, 
he saw that the pigment cells had accumulated around the blood- 
vessels, and that, though they still preserved their contractility, their 
processes were less branched and numerous than natural. On further 
examination, he now observed that these processes began to penetrate 
the walls of the adjacent capillaries and small veins, causing an 
obstruction to the onward movement of the red corpuscles on their 
proximal side, while a clear space was observable on their distal side, 
occupied only by serum. And now one of two things occurred : either 
the process of the cell broke off, and was swept away by the blood 
current, or the whole cell gradually squeezed itself through the capil- 
lary wall (the part within the vessel becoming greatly attenuated and 
elongated) until it also was carried away. In the former case, the 
cell, shorn of part of its substance, still remained outside the vessel ; 
in the latter, it of course disappeared entirely. As regards the time 
occupied in these phenomena, Dr. Saviotti finds that the cell processes 
penetrate the vessels in a period varying from three to six hours, and 
that it takes about the same length of time for the whole cell to follow 
and to be washed away from the internal surface, to which it long 
remains adherent. 
Bivalved Entomostraca from the Coal-measures of South Wales.—Some 
very important papers have lately been contributed by Professor 
Rupert Jones to the pages of the ‘ Geological Magazine. The papers, 
dealing as they do with the identification and description of several 
species, are too long for abstract, but those interested in the subject will 
do well to refer tothem. In the ‘ Geological Magazine’ for May, one 
of these papers is accompanied by a handsome plate. 
The Fibres of the Pregnant Uterus.—A letter, dated June 4th, is 
contributed to the ‘ Lancet’ by Mr. H. Bengafield, in which the writer 
puts a question that may possibly be answered by some of our readers. 
It is as follows :—Kolliker, in his ‘Human Histology,’ describes the 
development of the fibres in the pregnant uterus thus :—“ Instead of 
a length of 0:002—0-005'", and width of 0:002'", they attain in the 
second half of the sixth month a length of 0:1—0°25'", and a width 
of 0:004—0:006'". Consequently their length is increased from seven to 
