57i 
Constituents of the Cell . 
sharply, or even more distinctly, the larger microsomes and 
various other proteid granules, such as leucoplasts, when 
present ; and the result is only confusion and uncertainty (cf. 
Fig. 12 ). Boveri (’95) states that the egg of the Sea-Urchin 
contains numerous granules which stain as deeply with iron- 
haematoxylin as the centrosomes. No treatment has yet 
enabled me to see these bodies more distinctly than after 
simple staining with the gentian-violet-eosin combination 
recommended by Farmer (’94), or according to the fuchsin- 
iodine-green method used by Zimmermann. The substitution 
of acid fuchsin for fuchsin in the last mixture seems to offer 
no advantages. 
Since the centrospheres are relatively so small, the chances 
of their concealment are correspondingly great. Thus, unless 
a section be taken in the right plane, they may be easily 
hidden beneath the nucleus, as probably in Fig. 2. Or, if 
a section be not very thin and the centrospheres in a given 
cell lie below the surface of the section, covered by a thin layer 
of the granular cytoplasm, they are very effectually concealed. 
These possibilities must be borne in mind in the consideration 
of any account of the presence or absence of centrospheres. 
It may be remarked that these results of my experience in 
the study of these bodies coincide, in the main, with those of 
Guignard (’94). It is also of interest to observe that Boveri 
remarks, in his last admirable discussion (’95) of the centro- 
some question, upon the importance of c the clear space and 
the radiations , for the recognition of the centrosome in many 
animal cells. One may be pardoned serious doubts whether 
all the appearances heretofore interpreted as centrospheres by 
zoologists really justify such interpretation. 
Among the most clearly recognizable plant centrospheres 
yet seen are those figured for Sphacelaria by Strasburger (’92) 
and the writer (’94), and for Pellia by Farmer and Reeves 
(’94), and by Strasburger (’95). I have been able also to 
observe them in material of P. epiphylla collected near Balti- 
more. In both of these cases cytoplasmic radiations render 
considerable aid to the observer. The relation of the centro- 
R r 2 
