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of these green, bodies in such animals as Hydra viridis and Span- 
gilla. One theory is, that the green bodies are true chlorophyll 
granules ; another, that they are not produced by the animals 
themselves, but are parasites ; and a third, that in the Protozoa, at 
all events, they are merely portions of vegetable organisms which 
have been absorbed. 
Herr Brandt set himself to demonstrate their true character ; and 
he found that these green bodies from Hydra and Spongilla, 
examined microscopically with high powers, were not of a uniform 
colour like the ordinary chlorophyll bodies of plants, but contained 
also hyaline protoplasm, and on treatment with heematoxjdin he 
ahvays found a definite cell-nucleus. These characters, he considers, 
prove that the green bodies are really unicellular organisms, mor- 
phologically independent ; and he describes them as two new genera 
of Algae — one green, Zodchloralla, found in Protozoa, Sponges, 
Hydrozoa, and Turbellaria; the other yellow, Zodxantliella, found 
in some Eadiolaria, Hydrozoa, and Actinia}. Hot only are 
these organisms morphologically independent, their physiological 
independence can be shown also ; for if individuals of Zodchlorella 
are isolated from their host, they will live for days, or even weeks, 
and “when exposed to light they are able to develop starch 
grains.” 
Brandt demonstrated the mutual relation between the animal 
host and the vegetable lodger thus : — He kept animals in which the 
Algaj were well developed in carefully filtered water, and found 
that though the animals throve well whilst thus deprived of any 
food received in a natural manner — being nourished by tire Algaj — 
as soon as they were placed in a darkened situation, the Algaj, 
unable to live without the light of the sun, died, and the animal 
died too, of starvation ; for the filtration of the water allowed no 
food to reach it. This proves that the Algae contribute to the 
support of their host. “ So long as the animal contains but few or 
no green or yellow cells it is nourished like a true animal, by the 
absorption of solid organic materials. As soon as it contains a 
sufficient amount of Algae it is nourished like a true plant, by the 
assimilation of inorganic materials. It ought to resume its original 
