204 
PROGRESS OF MICROSCOPICAL SCIENCE. 
Proportions of Bed and White Blood-corpuscles in Health and Disease. 
— The instrument which we described some time ago for estimating the 
number of blood-corpuscles has been turned to practical account by 
its inventor, M. Hayem. The ' Lancet ' (Aug. 5) says that M. Henri 
Bonne has described a series of observations on the proportion of 
white to red blood-corpuscles in different diseases, made under the 
direction of M. Brouardel. The examinations were made daily by 
the methods of MM. Malassez and Hayem. Among the facts recorded 
are the following. In a patient with cancer of the breast, before its 
removal by operation, the white corpuscles were 1 to 48 red ; three 
days afterwards they were 1 to 28 and 1 to 23. When suppuration 
was established the proportion fell to 1 in 60, 1 in 90, and at last, 
when the pus ran freely, 1 in 400. In two cases of iliac abscess the 
leucocytes, before the abscess was opened, were 1 to 18 in one case, 
1 to 38 in the other. Immediately after, the white corpuscles fell to 
1 in 132 in one case, and to 1 in 130 in the other. In other abscesses 
the same result was obtained. It thus appears that the formation of 
pus in an abscess coincides with a considerable increase in the 
leucocytes in the blood, and that the increase disappears when the 
abscess is opened. Similar results have been found in other suppura- 
tive maladies. In small-pox on the fifth day the leucocytes were 1 in 
450 ; on the sixth day 1 in 48 ; on the seventh day 1 in 150 ; on the 
ninth day 1 in 236. In a case of suppurating pneumonia the white 
corpuscles at death on the ninth day were 1 to 40 red. Other 
influences besides confined suppuration cause leucocytosis. An 
eruption of herpes in one patient raised the number in four days from 
1 in 80 to 1 in 90. In typhoid fever the leucocytes are very numerous 
about the seventh day, but fall to from 1 to 70 to 1 to 500 by the 
seventh day. Their number does not coincide with variations of 
temperature. 
On the Microscopic Observation of Minute Objects. — At the meeting 
of the Academy of Sciences of Philadelphia (May 9), Professor Frazer 
remarked that he desired to put on record a thought relating to 
Helmholtz's now famous establishment of the limit of vision through 
the microscope. As this limit was determined by half the length of 
a wave of light, and since the wave-lengths of the most refrangible 
rays of the light spectrum (i. e., the violet) are somewhere near the 
^Y-uoo P^^* inch, the conclusion was reached that nothing 
more minute than the yT4Vo^^ P^^* of mch. could be seen. But 
actinic waves or others of smaller length (of greater refrangibility 
too) in passing through a substance on which are lines or other mark- 
ings less than tj^Vw i^^^ apart, may be altered to light waves, 
and become visible, provided that the substance through which they 
pass is capable of fluorescing — i. e., increasing their wave-length — and 
provided the distance apart of the marks to be seen is not less than 
one-half the wave-length of such actinic waves. 
Death of Professor Ehrenberg. — Although this is not the place 
for a necrological notice, we feel that an exception may be made 
in the case of Herr Ehrenberg, an Honorary Fellow of our Society, 
