397 
There has been considerable discussion as well as considerable 
divergence of opinion in regard to the structure of the chlorophyll- 
grains. What I have to relate refers solely to what I have seen, 
or think that I have seen, in the chromatophores of the plants to 
be mentioned. 
Any countryman is entitled to an opinion on all subjects, pro- 
vided that the tools which he uses in his ‘investigations are as good 
as can be had, that he uses them intelligently and that he describes 
his observations as he thinks he has seen the objects, holding his 
imagination in check, and always bearing in mind that he is human 
and therefore « prone to err.” The tools in this special case are 
the 1/ and the ¥ inch objectives, both by Zeiss, and both apochro- 
matic ; Spencer’s homogeneous-immersion 1's, N. A. 1.35 ; Reich- 
ert’s semi-apochromatic, oil-immersion tz, N. A. 1.40; Gundlach’s 
homogeneous-immersion as, N. A. 1.22; an achromatic condenser ; 
Powell and Lealand’s 2-inch, and Zeiss’ 8 and 27 eye-pieces, all 
compensating. The conditions are that the leaf shall be studied 
in the 4 per cent. sugar-solution with no preparation, except in 
Some cases, the free-hand sectioning of the object and its imme- 
diate examination. 
In reference to the structure of chloroplasts, F. Schwartz says* 
that they are formed of fibrilla, which are arranged in a network, 
yet lie side by side attached to one another by what he calls 
metaxin. Such structure is not visible in the chromatophores of 
Astrophyllum sylvaticum nor in those of any other plant which I 
ave examined; and likewise A. Meyer says} that he has failed to 
See the fibrille and does not hesitate to add that Schwartz’s ob- 
servations are incorrect. Schimper, in an extended treatise on the 
Subject Says} that the simplest chromatophores consist of a color- 
less Protoplasmic substance without any visible internal structure 
°F contents, and that this is sometimes the case during the whole 
of their existence, as with most leucoplasts. | | 
Structure is so plainly visible on the external surfaces of the 
chloroplast of Astrophyllum sylvaticum that I confess to consider- 
OBS aes has 
* Cohn’s Beitr. z, Biol. Pflanzen, 5: 1-224. 
t Bot. Ztg. 46 : 636. : 
6. gf Tingsheim’s Jahrb, f, wiss. Bot. 16: 1-247. Cf, Journ. Roy. Micros. Soc. (II) 
+ 640, ; J 
