es Bennett in this country, and by Virchow and Max
Schultze in Germany. Not, however, until the decade ending in 1890 was
it realised what a large amount of new work on the corpuscular elements
of the blood had been done by Hayem, and by Ehrlich and his pupils. As
successive papers were published, especially from German laboratories,
it became evident that the systematic study of the blood by various new
methods was resulting in the acquisition of a large number of facts
bearing on the pathology of the blood; though it was still difficult to
localise many of the normal haematogenetic processes. The production of
the various cells under pathological conditions, where so many new
factors are introduced, must necessarily be enshrouded in even greater
obscurity and could only be accurately determined by patient
investigation, a careful arrangement and study of facts, and cautious
deduction from accumulated and classified observations.

The pathology of the blood, especially of the corpuscular elements,
though one of the most interesting, is certainly one of the most
confusing, of all departments of pathology, and to those who have not
given almost undivided attention to this subject it is extremely
difficult to obtain a comprehensive and accurate view of the blood in
disease. It is for this reason that we welcome the present work in its
English garb. Professor Ehrlich by his careful and extended observations
on the blood has qualified himself to give a bird's-eye view of the
subject, such as few if any are capable of offering; and his book now so
well translated by Mr. Myers must remain one of the classical works on
blood in disease and on blood diseases, and in introducing it to English
readers Mr. Myers makes an important contribution to the accurate study
of haemal pathology in this country.

Comparatively few amongst us are able to make a cytological examination
of the blood, whilst fewer still are competent to interpret the results
of such an examination. How many of our physicians are in a position to
distinguish between a myelogenic leukocythaemia and a lymphatic leukaemia?
How many of us could draw correct inferences from the fact that in
typhoid fever there may not only be no increase in the number of certain
of the white cells of the blood, but an actual leukopenia? How many
appreciated the diagnostic value of the difference in the cellular
elements in the blood in cases of scarlet fever and of measles, and how
m