Amongst the various forms of abdominal tumour, few are so dif-
ficult of detection as those which depend upon certain diseases of
the kidney. There are many diseases of the kidney which are
accompanied by no enlargement, and in some, again, the size of the
organ is decidedly diminished. Such forms of disease, which
cannot be detected by any tumour of the part, do not, of course,
come within the scope of the present investigation ; but, on the
other hand, the kidney is often enormously enlarged, forming a dis-
tinct abdominal tumour. The chief diseases under which I have
known this condition to exist are, when numerous cysts have been
developed in the substance of the kidney ; when puriform matter
has collected in the pelvis, and converted the distended kidney into
a bag of pus ; when fungoid or malignant changes have taken
place in the kidney; when fungoid matter or blood has been
accumulated in the pelvis.
I have known the enlarged kidney to be mistaken for disease of
the spleen — of the ovary — of the uterus — and for a tumour deve-
loped in the concave part of the liver ; nor is it perhaps possible, by
the greatest care and the most precise knowledge, altogether to
avoid such errors ; and therefore the more necessary it is to prose-
cute the investigation.
