OBSERVATIONS ON THE STRUCTURE OF THE SPLEEN, 863 
the meetings of the Scientific Committee of the Royal 
Horticultural Society are given, will show that Mr. Berkeley 
was the first to detect mature oospores in the potato plant. 
At one of these meetings he described the bodies, brought 
a sketch, and gave the exact dimensions. As Mr. Berkeley 
could find no trace of the Peronospora in the plants examined 
by him, he could not associate the two things together ; but 
in the plants which came under my examination | found 
not only the normal Peronospora, but the mature resting- 
spores and the oogonia and antheridia in various stages of 
growth and in conjugation. The mature oospore is globose 
or slightly oval, brown becoming at length black-brown, 
and covered with nodosities ; it measures from one seven- 
hundredth to one thousandth of an inch in length. A figure 
of it was published in the ‘Gardeners’ Chronicle’ for July 
24th last; it has also been illustrated in ‘ Nature” and 
elsewhere. 
OssERVATIONS on the SrructurE of the SpLEEN. By Dr, 
E. Kuein, F.R.S. (With Plate XXI.). 
Tue structure and function of the spleen has at all times 
been one of the most favourite subjects of discussion with his- 
tologists. It is chiefly its great importance in pathology that 
has made it an object of repeated investigation, The spleen is 
so complicated an organ, and its investigation combined with 
so many difficulties, that it is no wonder that even the prin- 
cipal points with regard to its structure are not yet definitely 
settled, being still a matter of controversy. Experiment has 
done very little hitherto with reference to the function 
of the spleen; the whole doctrine of its function rests, there- 
fore, almost entirely on anatomical investigation. Generally 
the spleen is regarded as to a certain extent analogous to a 
lymphatic gland, in virtue of its containing masses of adenoid 
tissue, first in the sheath of arterial branches, and secondly 
as special elliptical or spherical collections—the well-known 
Malpighian corpuscles—in connection with small arteries. 
From this and from the fact that the trunk of the splenic vein 
always contains in the normal condition an abundance of 
lymphoid cells or colourless blood-corpuscles, it has been 
concluded that these cells are produced in the spleen. 
1 See June 19, p. 795 and July 10, p. 46, Mr. Berkeley at first took the 
oospores for a species of Protomyces. 
2 July 22, p. 234. 
