272 THE AMERICAN NATURALIST. [VoL:; XXXIIL. 
Josum. But in other respects the gametophyte and embryo of B. vir- 
- ginianum agrees with what is known of other Ophioglossacee. The 
author points out a similarity in form between the prothalli of B. vir- 
ginianum and Hycopodium annotinum, while a likeness is also found in 
the same organs of Ophioglossum pedunculosum and L. cernuuem and 
L. inundatum, showing two types of the eee in the Ophio- 
glossacez as in the Lycopodinez. H. MR. 
Proteolytic Enzyme of Nepenthes.1— This paper is in continuation 
of one published by the same author in 1897. He concludes that 
the enzyme from the pitchers of Nepenthes is comparatively a very 
stable one. High temperatures and alkalis gradually lessen its 
activity, but do not completely destroy its power of digestion unless 
strong means are employed. The enzyme is of the nature of a tryptic 
ferment closely resembling that found in germinating seeds, like which 
it is active only in an acid medium. The author considers that he 
has fairly demonstrated the enzyme to arise from a zymogen in the 
gland cell of the pitcher. HMR 
Nucleus of the Yeast Plant.? —According to this last account the 
cells of yeast certainly possess what the author terms a nuclear appa- 
ratus. This consists in the early stages of fermentation of what is 
called a homogeneous nucleolus in close contact with a vacuole con- 
taining a chromatin network. In later stages the “ chromatin-vacu- 
ole ” may have disappeared, the chromatin material being found as 
fine granules in the protoplasm. In the young stages there may be 
more than one “ chromatin-vacuole,” which later appear to fuse. The - 
division which accompanies budding is direct, and takes place in the 
constriction between mother and daughter cell. If the author is 
properly understood, in spore formation the chromatin is absorbed 
by the nucleolus, to appear later in the form of fine grains (chromo- 
somes ?). The nucleolus elongates into a dumb-bell shape in the 
division preceding spore formation, and then constricts into two. 
Subsequent divisions forming four or even more new nucleoli may 
take place. A wall forms around these, and the spores are formed. 
The author does not demonstrate very definitely the relation of the 
nuclear apparatus of the spore to that of the vegetative cell. It 
1 Vines, S. H. The Proteolytic Enzyme of Nepenthes (II), Ann. Bot., vol. xii 
(Drami, 1898), Pp. 545-555- 
Wager, Harold. The Nucleus of the Yeast Plant, Ann. Bot., vol. xii 
(December, 1898), pp. 499-537, Pls. XXIX, XXX. 
