1330 
also of the opinion that the precipitate belongs to the group of the 
proteins, as far as its behaviour towards reagents is concerned. 
The precipitates caused by ammonium carbonate in the cell-sap 
of Spirogyra and of other plants, have also been investigated by 
Prerrer'). In his opinion they are composed of protein tannate and 
give reactions both with protein- and with tannin-reagents. 
Lorw and Boxorny’) have written numerous papers on the subject 
of precipitation in living plant cells by various basic substances. In 
these publications, the same points generally have been stated, so 
that they can here be dealt with together. 
In the opinion of these two investigators the precipitates whicn 
have been caused in the cells by ammonium carbonate, antipyrine 
and caffeine consist of active protein. The bodies of which the preci- 
pitates are composed, called by these writers proteosomes, can be 
formed both in the protoplasm and in the cell-sap. According to 
Loew and BokorNy the formation of proteosomes is a real vital 
reaction. When the cells have been killed, the reagents mentioned 
cannot any longer bring about the phenomenen, because the active 
protein has been changed into passive protein. 
The two authors describe peculiarities of the precipitates and 
mention positive results which they obtained with various protein 
reagents. The precipitates are siated to be composed either exclusi- 
vely of active protein or they contain also other substances, such as 
tannin, but it is emphatically declared in this connection, that the 
admixture of other substances is “unwesentlich”. 
1) W. Prerrer, Ueber Aufnahme von Anilinfarben in lebenden Zellen. Unter- 
suchungen aus dem botan. Institut zu Tübingen. 2. Bd. 1886—1888. p. 239 ff. 
2) QO. Loew und Tu. Boxorny, Ueber das Vorkommen von activem Albumin im 
Zellsaft und dessen Ausscheidung in Körnchen durch Basen. Bot. Zeit. 45. Jahrg. 
1887. p. 849. — Ueber das Verhalten von Pflanzenzellen zu stark verdünnter 
alkalischer Silberlösung. Bot. Centralblatt. 10. Jahrg. 1889. XXXVI[L. Bd. p. 581 
and 614. XXXIX. Bd. p. 369. XL. Bd. p. 161 and 194. — Versuche über aktives 
Eiweiss für Vorlesung und Praktikum. Biologisches Centralblatt. 1891. XI. p. 5. — 
Zur Chemie der Proteosomen. Flora. 1892. Ergänzungsb. p. 117. — Aktives Eiweiss 
und Tannin in Pflanzenzellen. Flora. Cl. 1911. p. 113—116. Autoreferat. Botan, 
Centralblatt. 32. Jahrg. 1911. I. Halbjahr. Bd. 116. 1911. p. 361. 
Tu. Boxorny, Neue Ustersuchungen über den Vorgang der Silberabscheidung 
durch actives Albumin. Jahrb. f. wiss. Bot. XVIII. Bd. 1887. p. 194. — Ueber 
die Eimwirkung basischer Stoffe auf das lebende Protoplasma. 1. e. Bd. XIX. i888. 
p. 206—220. — Ueber Aggregation, |. c. Bd. XX. 1889. p. 427. — Zur Kenntniss 
des Cytoplasinas. Ber. d. d. bot. Gesellsch. Bd. VIII. 1890. p. 101. — Zur Pro- 
teosomenbildung in den Blättern der Crassulaceen. 1. c. Bd. X. 1892. p. 619. — 
Ueber das Vorkommen des Gerbstoffes im Pflanzenreiche und seine Beziehung 
zum activen Albumin. Chemiker-Zeit. 1896. No. 103. p. 1022. 
