1337 
antipyrine, caffeine and other basic substances precipitates which 
agree with those occurring in living cells, the following method 
may be adopted. A number of Spirogyra-filaments are taken, washed 
out with distilled water, which is allowed to drip off as much as 
possible and then they are heated to 60°, dried as well as possible 
by means of gentle pressure between filter-paper, and extracted 2 or 
3 times with a mixture of 4 parts of ether and 1 part of alcohol, 
such as is used in the extraction of tannin from gallnuts; the fluid 
obtained is filtered and evaporated in a vacuum. The residue, which 
resembles gallnut-tannin, is dissolved in a little distilled water and 
filtered. We thus obtain a solution, which gives all the possible 
tannin reactions, with ferric salts, potassium bichromate, egg-white 
and gelatin solutions, caffeine, antipyrine ete. 
The precipitates with antipyrine and caffeine solutions, with pyridine 
and quinoline-vapour, and other basic substances completely resemble 
those occurring in living cells: little spheres or globules which show 
Brownian movement and gradually aggregate to larger masses, 
which on the addition of water dissolve and behave towards reagents 
as tannin precipitates, all of which completely resembles what we 
observe in living cells. 
From the above experiments it is evident that what Loew and 
BokorNy take to be reactions of active protein are in reality none 
other than reactions of tannin and the proteosomes none other than 
precipitates of different basic substances with tannin. It is farther 
evident that after death these precipitates can be as distinctly 
produced as in living cells and can therefore hardly be called vital 
reactions. 
The question what substances the precipitates can contain in addition 
to tannin-compounds is more difficult to answer than it was to 
demonstrate the tannin character of the precipitates in living cells. 
That other substances may be present in the precipitates, is already 
clear from observations on cells containing red colouring matter as 
well as tannin in solution in the cell sap. The precipitates take up 
the red colouring-matter and large red-coloured spheres finally arise 
through the aggregation of many globules. 
The question whether the intravital precipitates can contain protein 
will now be dealt with. As already stated Pperrer *) assumes that 
the precipitate which is produced in Spirogyra by ammonium 
carbonate, consists of protein and tannin, which, according to 
him, both occur in solution in the cell-sap. The acids present in the 
1) 1. ce. p. 239. 
