1905] CURRENT LITERATURE 427 
division (homotypic). There is no true resting period between the two mitoses, 
the chromosomes which leave the heterotypic figure pass morphologically 
unchanged into the homotypic. 
The chief points of difference between ALLEN’s account and that of FARMER 
and Moore are briefly as follows: FARMER and Moore fail to find the organi- 
zation of two threads preliminary to the formation of the single spirem which 
emerges from synapsis. They recognize only one longitudinal fusion of this 
spirem, which is regarded as preliminary to the formation of the chromosomes 
of the homotypic : mitosis. The pairs of chromosomes of the heterotypic mitosis. 
significance of the reducing division cannot be considered here. The accounts 
themselves rest on matters of fact and not of interpretation, and one or the other 
is likely to fall, for it is hardly possible that both can be right, especially since they 
treat of the same form. 
ALLEN presents at the end of his paper a thorough and very interesting dis- 
cussion of his conclusions in their relation to problems of heredity and hybridi- 
zation.—B. M. Davis. 
THE suBJEcT of soil inoculation for legumes has recently acquired a.wide- 
spread interest in this country, first, from numerous popular accounts relating 
to the subject, and again on account of a widely advertised commercial product. 
by which is it claimed the proper bacteria can be introduced into the soil. For 
this reason Moore’s account? of his work in this field is of special interest. 
The first part of the bulletin is a general historical account dealing with the 
various methods by which nitrogen is fixed in the soil, and leading up to the dis- 
coveries of HELRIEGEL and WILLFARTH connecting the fixation of nitrogen by 
legumes with the tubercles on the roots, and the discovery of bacteria in these 
tubercles by Worontn. The chief results of Moore’s investigations may be 
briefly stated as follows. The root-tubercle organism exists in three well-defined 
h 
threads” passing through the tissues of the host. These curious fungus-like 
structures have often been observed and figured, and have been the objects of 
much discussion. Their explanation is that they are zooglaea-masses composed 
of numerous minute bacteria. These minute bacteria soon give rise to larger 
rod-shaped forms which may or may not be motile. These finally produce the 
branched forms peculiar to the Iegume-nodule. It is only this last form that 
is of any benefit to the plants, for in this state the bacteria are broken down and 
their contents made available. The name of the organism is changed to Pseudo- 
monas radicicola, since the motile rods have flagellae only on one end. The 
ooRE, G. T., Soil inoculation for legumes, etc., U. S. Dept. of Agric., Bureau. 
of Plant Focus, Bull. 71, pp. 72. pls. 10. 1905. 
