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that these cells were in some way related to the function of nutri- 
tion,* particularly as stores of reserve-material. 
In 1871 a very remarkable contribution to our knowledge was 
made by Cienkowski, f who strongly expressed his opinion that 
these yellow cells were parasitic algse, pointing out that our only 
evidence of their Radiolarian nature was furnished by their constant 
occurrence in most members of the group. He showed that they 
were capable not only of surviving the death of the Radiolarian 
for a week or more, but even of multiplying, and of passing through 
an encysted and an amoeboid state (phenomena which, while not 
indeed deciding the significance of the yellow cells, are yet in the 
highest degree foreign to the life processes of the Radiolarians), and 
urged their mode of multiplication, and the great variability of their 
number within the same species, as further evidence of the justice 
of his view. 
The next important work was that of Richard Hertwig, J pub- 
lished five years later. He inclined to think that these cells some- 
times developed from the protoplasm of the Radiolarian, and failed 
to verify the observations of Cienkowski, suggesting that, as in 
higher organisms, one portion might continue in life for some time 
after the rest, without thereby proving its distinctness, and con- 
cluding with Haeckel, that the yellow cells “ fiir den Stoffwechsel 
der Radiolarien von Bedeutung sind,” and that their main function 
was to store up reserve-material, starch, &c., until the organism 
should require it. In a later publication, however, § he hesitates to 
decide as to “ this most controverted point of Radiolarian mor- 
phology,” and limits himself to suggesting two considerations in 
favour of their parasitic nature; first, that yellow cells are to be 
found in Radiolarians which possess only a single nucleus, and that 
the origin of their nuclei from that of the Radiolarian is highly 
improbable; and secondly, that they are absent in a good many 
species. 
A later investigator, Dr. Brandt || of Berlin, has completely con- 
* “ Amylum in d. gelben Zellen d. Radiolarien,” Jena Zeitschr ., 1870, p. 532. 
t “ Ueber Schwarmerbildung bei Radiolarien,” Archil >. Mikr. Anat., 1871. 
+ Zur Histologic d. Radiolarien , Leipzig, 1876. 
§ “Der Organismus d. Radiolarien,” Jena DenTcschriften , 1879. 
|| “ Untersuchungen an Radiolarien,” Monatsb. Akad. Wiss ., Berlin, 1881, 
p. 388. 
