5 
1903] CURRENT LITERATURE 155 
comparable to the tetrad divisions in higher plants, meaning the two mitoses in 
the spore mother-cell. The nucleus passes through a synapsis condition before 
the first mitosis. The spindle is intranuclear with small granular bodies at 
the poles asin others of the Peronosporales. In the second mitosis the 
spindle is less distinct, as Stevens noted in Albugo. The number of chromo- 
somes appears to be about the same in each mitosis. Rosenberg regards the 
synapsis as indicating a reduction of the chromosomes, in agreement with the 
generally accepted history of the spore mother-cell, and considers its presence 
in relation to the two mitoses as establishing analogies with these events. 
The reviewer has recently discussed the behavior of the nucleus during 
gametogenesis in the Phycomycetes™ and regrets that he could not have 
included Rosenberg's views in that account. However, his opinions are not 
changed by these results. It is not established that synapsis has any relation 
to reduction phenomena in the thallophytes, and it is also — reported 
among higher plants in tissues where there is no reduction. e number of 
mitoses in the gametangia of Phycomycetes is quite variable. There is only 
one in the oogonium of Saprolegnia and in certain species of Peronospora 
and Pythium. This mitosis is probably a phylogenetic reminiscence of times 
when many gametes were formed in these gametangia. A second mitosis is 
probably merely a continuation of the tendency to multiply the nuclei and 
would be carried farther if nutritive conditions allowed. The second mitosis 
is more likely to be found in the ooplasm, because that portion of the cell is 
unquestionably better nourished, which explains its entire or partial absence 
in the periplasm. There is excellent evidence that the second mitosis is 
weaker in kinoplasmic material than the first, thus showing the effect of unfa- 
vorable conditions in the cell. 
This is not saying that reduction phenomena may not take place just pre- 
vious to the mitoses in the gametangia of Phycomycetes, but comparisons 
between these mitoses and the events in the spore mother-cell are not likely 
to have much value in establishing the supposition. To the reviewer the 
probabilities seem all against the existence of reduction phenomena previous 
to gametogenesis in plants, for it is more natural to expect it either imme- 
diately after the sexual act or at the end of a sporophyte generation. The 
proof must come through studies of the nucleus at various periods of ontogeny 
and the evidence will accumulate slowly. We do not know of any better 
forms for such investigations than some of the Peronosporales, unless they be 
certain Chlorophyceae which have not received their fair share of attention 
in the cell studies of recent years.—B. M. Davis. 
ROTHERT has studied the effects of ether and chloroform on the sensibility 
of microorganisms,” Knowing that narcotics affect the various functions of 
* Davis, B. M., Oogenesis in Saprolegnia. Bot. GAZ. 35: 339-342. 1903. 
7? ROTHERT, W., Ueber die Wirkung des Aethers und Chloroforms auf die Reiz- 
bewegungen der Mikroorganismen. Jahrb. Wiss. Bot. 39: 1-70. 1903. The title is 
