1336 
Loew and Boxorny') declare the formation of protosomes with 
ammonium carbonate, antipyrine and caffeine to be a true vital 
reaction. They say that when the ceils are dead, formation of proto- 
somes can no longer take place, because the active protein has 
become passive. I shall proceed to show how, starting from dead 
material, precipitates can be produced with -antipyrine, caffeine and 
other basic substances, which completely agree with those observed 
in living material. 
That in dead cells of Spirogyra no precipitates occur with the 
above basic substances, is simply due to the fact that the dead 
protoplast and the cell-wall allow the tannin to escape. A portion 
of the tannin gets outside the cell and another portion enters into 
combination with the protein-substances present in the cell. It is 
specially fixed in the nuclei and the pyrenoids. Now antipyrine, 
caffeine and other basic substances can obviously no longer cause 
any precipitate in the vacuole. 
It can be proved as follows that in dead Spirogyra part of the 
tannin passes out. Pieces of Spirogyra-filaments are placed between 
slide and cover-slip in a 1°/, solution of egg-white or in a ‘/, °/, 
gelatin or glue solution. These colloids do not penetrate into the 
cells and cannot therefore form any precipitate with the tannin of 
the cell-sap. When carefully heated above a micro-flame, the cells 
are successively killed. The tannin passes through the protoplasmic 
layer and cell-wall and forms a precipitate in the egg-white-, gelatin- 
or glue-solution. On careful heating the precipitate lies immediately 
against the Spirogyra-filament. The cells which are still alive are 
not surrounded by a precipitate. It can be established by using 
solutions of ferric salts, and other tannin reagents, that the precipi- 
tate formed outside the filament is a tannin precipitate. 
When Spirogyra has been slowly heated in water to 60° in a 
test-tube placed in a water-bath, it dies. In this case much tannin 
usually combines with the protein present in the protoplast and only 
a little leaves the cell. When a large quantity of Spirogyra was 
heated to 60° in very little water, the liquid sometimes gave after 
filtration only a very weak tannin reaction with ferric salts, whilst 
the nuclei and pyrenoids always gave a distinet reaction. The nuclei 
and pyrenoids also gave a distinct tannin reaction with iodine in 
potassium iodide solution. When sufficiently washed out with water 
they show a fine red violet coloration. 
When starting with dead material, it is desired to produce with 
aa ci Loew and Ta. Boxorny, Ueber das Verhalten von ['flanzenzellen zu stark 
zardünnter alkalischer Silberlösung. Bot Centralbl. Bd. XXXVIIL p. 614. 
