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Naegeli’s Experiments on Living Cells. 
SHORT notice of Carl von Nageli's paper, ‘« Uber oligodynamische 
Erscheinungen in lebenden zellen,” concerning the fatal effect 
of ‘“nominally”” pure water on living cells, appeared in NaTuRAL 
SCIENCE (May, p. 333). The following is an account of the experi- 
ments by which Nageli arrived at his conclusions. The record of 
this work, which was carried on in his laboratory at Munich, was 
found by Schwendener among his papers after his death. Professor 
Cramer, of Ziirich, went carefully over the ground a second time and 
obtained the same results as his old master. 
The research, we are told by Schwendener, dates from the year 
1880. Dr. O. Léw and Dr. Bokorny had recently published a paper 
on the reduction of silver salts by living protoplasm. While verifying 
for himself the results arrived at by these gentlemen, Nageli was led - 
to turn his attention from the effect of living cells upon silver salts to 
the reverse action of the silver salts on living cells. 
The Spivogyva experimented on is a very common fresh-water 
Alga; it is composed of long cylindrical filaments, divided up at 
regular short intervals into cells, with spiral parietal bands of chloro- 
phyll. The spirals may be single or double, and they, as well as the 
cells, vary in size in the different species. These differences affected, 
to a considerable extent, the sensitiveness of the plant under examina- 
tion; the more compact the spirals the greater the resisting power of 
the cells. It was also found that resistance to any hurtful influence 
was at its maximum towards the close of the day, when there was a 
great accumulation of assimilation products in the chlorophyll bands. 
In the early morning, when these were withdrawn and dispersed 
through the cells, the plant was much more sensitive. 
The alkaline solution of the silver salt used by Nageli in his 
experiment was the one prepared by Dr. Low (containing 1 Ag NO,, 
1 NH,, 3°6 K,O to 100,000 volumes of water), which killed the plant 
by poisoning it; the cells lost their turgidity, the protoplasmic layer 
shrunk away from the walls, the chlorophyll bands changed colour 
and gradually became disintegrated. With further dilution the cells 
still died, but in a totally different manner; the turgidity of the cells 
and the protoplasmic layer remained unaffected, the chlorophyll 
bands alone seemed to be sensitive, they shrunk together with the 
