ON WANDERING CELLS IN ECHINODERMS. 91 
the “cancer-cells,” or possibly by some as yet unknown virus 
casually associated with these cells—is contradictory to the 
view set forth by Cornil and Ranvier (28, p. 199, et seq.) that 
the mesoblastic stroma forms the prime part of the tumour 
growth—a view, however, which has not found favour with 
other writers. 
If the stroma of the growth is regarded as above suggested, 
the process of formation is quite in accordance with the 
deposition of fibrous material around other irritative objects. 
Indeed, without necessarily upholding “ vitalistic properties ”’ 
on the part of the tissues, a matter so vehemently fought 
against by Haidenhain (No. 35), there are two phenomena, 
related to the process of inflammation, which are especially 
beneficial to the body at large owing to the shelter they afford : 
1. The exudation of fluid from the blood-vessels, whereby 
the lymphatic vessels are flushed, and any poisonous substance 
present is diluted before it is submitted to the purifying action 
of the lymphatic glands. 
2. The formation of fibrous tissue round an irritant, which 
tissue of itself and by its subsequent contraction tends to 
prevent the spread of the local morbid condition. 
B. We now come to the consideration of the part played by 
wander-cells in the normal economy of animals. This is so 
vast a subject—a subject with such numberless and crooked 
bypaths—that we cannot pretend to go at all fully into it, and 
we shall confine our attention particularly tu the power of 
ridding the system of effete matters by means of the interven- 
tion of wander-cells. 
It has been shown above that in many Echinoderms some 
substances are actually removed by the activity of such cells. 
Is this to be regarded as a process of ordinary excretion 
(urates, &c.)? All that can be answered so far is that both the 
slime collected from Asterias rubens and an extract of some 
thirty dorsal organs taken from the same species gave no results 
with the murexide reaction for uric acid. 
Griffiths (No. 31) has found uric acid as a constituent of the 
clear fluid contained in the “ stomach-sacs” in starfish; but 
