188 C. CLIFFORD DOBELL. 
degenerate. In order to obtain satisfactory material I 
accordingly made preparations from the kidneys of the 
cuttlefish while still alive, fixing the smears, etc., as 
quickly as possible. When this is done the results are 
practically always the same after a reliable method of treat- 
ment. Excellent fixation can be obtained with any of the 
good fixatives in ordinary use—sublimate-alcohol (hot), 
picro-acetic (hot), and Hermann’s solution being particularly 
good, especially the two former. The usual stains all give 
excellent results—even the very simplest giving quite ex- 
ceptionally good pictures. I have found Delafield’s heema- 
toxylin and borax carmine (Grenacher) as good as anything 
one could desire. I used both moist film preparations—made 
by smearing the kidneys on a coverslip—sections, and the 
following method :—A small piece of the kidneys, containing 
many parasites, was fixed, stained entire, and finally teased 
up in clove oil. Isolated individuals could be examined 
in this way with great ease, though moist film preparations 
are perhaps the best. And the results at which I arrived 
were these. There is a nucleus constantly present in 
the form of .a delicate network of chromatin and 
plastin. At no period in the living animal does it undergo 
a cycle of changes as described by Gonder. In addition to 
the network there are also to be seen in the cytoplasm—in 
greater or less numbers—particles which stain strongly 
with chromatin stains. (Cf. fig. 2.) From observations 
on a large number of organisms I am now convinced that 
this represents the normal condition of the nuclear material. 
It now. remains to answer the questions, ‘‘ What are the 
chromatin particles in the cytoplasm?” and ‘‘ What are the 
curious chromidial stages described by Gonder ? ” 
Regarding the former, I think it may be regarded as 
certain that the chromatin particles are—in part, at any rate 
—ingested food material. As I have already shown, the 
majority of individuals—all those, in fact, which have attained 
any size—possess a mouth. And this very obviously serves 
for the ingestion of food, which appears to be largely com- 
