Assays of the pink (Wghemoglobin-bearing) root . t _ tt- ui j 
dules of alfalfa, clover, and pea plants revealed the con- Botanical Exploration or the Guyana Highland 
Vitamin B 12 , Rhizobia, and Leguminous Plants 
Alfred P. Levin, Helen B. Funk, Moses D. Tendler, 
Barnard College and Columbia University 
Assays of in vitro cultures of root-nodule bacteria with 
Euglena gracilis var. bacillaris and with Ochromonas 
malhamensis confirmed that Rhiaobium meliloti, R. tri¬ 
folii, and R. leguminosarum synthesize vitamin B 12 , as had 
been shown previously. Additional studies showed that th 
ratio of the amount of the vitamin excreted to^xsATre- 
tained with the cells of R. meliloti was at least 1:2; of 
R. trifolii, at least 3:1; and of R. leguminosarum, at 
least 1: 1. 
root 
nodules of alfalfa, clover, and pea plants revealed the con¬ 
centration of vitamin Bj 2 to be 3 to 34 times greater than 
that in the root tissues. In the case of alfalfa, the con¬ 
centration of the vitamin in pink nodules was 400 per¬ 
cent greater than in white- nodules. 
Rhizobia isolated from pink nodules gave a different 
ratio of vitamin excreted to retained as compared with 
those for the bacterial cells grown in vitro. The in vivo 
ratios were for R. meliloti, 14: 1, and for R. trifolii, 
5:1. There was also an increase in the number of mole¬ 
cules of vitamin B a2 synthesized per bacterial cell in the 
nodules, this being especially marked for R. trifolii. 
Alternate Modes of Pion and Muon Decay 
and of Muon Capture 
S. Lokanathan, J. Steinberger, H. Wolfe, 
Columbia University 
We have searched for ihe following three processes: 
- + —»• e + + v 
contained no lipid. Nonspecific lipid was first localized in 
theca cells of preantrum-stage follicles; cholesterol in the 
succeeding early antrupar-lffage. Granulosa lipid, acidic or 
phospholipid in iiafctffe, appeared in atretic follicles of all 
types. The tlmetfinterna then, presumably, is the site of 
the production of ovarian hormones or of precursor sub¬ 
stance 
fsing the PAS technique, glycoprotein was inferred as 
component of the follicular fluid, the zona pellucida, and 
the basement membrane. The zona pellucida was thus 
demonstrated as a thin membrane in the primary fol¬ 
licle. The earliest manifestation of the secretion of fol¬ 
licular fluid was in the four-layered follicle. 
jc 
|X" + 
e + + y 
Cd* + e~ 
Tlie apparatus employer electronic counting techniques 
and was of considerably greater sensitivity than has 
previously been used for this purpose. Nevertheless, we 
have found no evidence for the existence of these reac¬ 
tions and find 
1) Rate (jt + —> e + 4- v) / ‘ate (jt + —>qT + v) <C 5 x 10 ° 
2) Rate ( (li + —> e + + y) /rate (g + -» + 2 V ) < 2 x KB 5 
3) Rate (jn' + Cd Cd^ + «-)/rate (|i" + Cd->Ag* + v) 
< 3x10 -3 . 
Present theory does not seem to provide an understand¬ 
ing of the smallness of these interactions compared with 
those that are actually observed. 
Cytochemistry of the Human Ovary 
Margaret E. Long and Earl T. Engle, 
Columbia University College of Physicians and Surgeons 
Ovarian histophysiological studies have long centered 
their interest on the identification of the cells that secrete 
ovarian hormones or related substances. Most of the en¬ 
lightenment on this subject has been obtained from stud¬ 
ies of animal ovaries. This paper presents a cytochemical 
analysis of preovulatory follicles in sections of resected 
human ovaries. 
Since ovarian hormones are fat-soluble steroids, lipid 
tests were correlated to identify the types of lipid and 
their distribution throughout normal follicular develop¬ 
ment and atresia. Reactive lipid substances, mainly cho¬ 
lesterol, were visualized in theca interna cells of healthy 
preovulatory follicles. The granulosa of normal follicles 
Bassett Maguire and David D. Keck, 
Neiv York Botanical Garden 
For 250 years naturalists have been lured to the Guyana 
Highland of northeastern South America by the great 
riches of plant and animal life that are to be found there. 
The sandstone table mountains that form the character¬ 
istic topographic feature of the region bear on their 
summits a flora that contains the highest incidence of 
endemism known from any part of the globe of like area. 
The Guyana Highland extends from near the Colombian 
boundary across southern Venezuela and British Guiana 
to Surinam. 
The New York Botanical Garden has been actively ex¬ 
ploring this region since 1944. Sixteen expeditions have 
been made by the Garden thus far, with four more now 
in progress. Some 18,000 numbers of plant collections 
have been made in sets of 6 to 10 each and by the end 
of the current season, which draws this exploratory phase 
of the Garden’s work in the Guyana Highland to a close, 
aproximately 150,000 specimens will have been taken. It 
is estimated that the area in all contains some 4000 to 
5000 endemic species and 100 new genera, large numbers 
of which are as yet undescribed. 
Changes in Three-Dimensional Shapes of 
Cells, within the Apical Meristem, 
during Cell Division 
Edwin B. Matzke, Columbia University 
Cells in tissues have some features in common with the 
units of certain inorganic systems; they differ, however, 
in their origin from preexisting cells. In the present 
study, 400 interphase cells and 400 dividing cells were 
investigated. Median sections of the stem tip of Ana- 
charis densa cut at 40 g and stained in Feulgen and 
ruthenium red were used, :pul the cells were examined, 
in toto, under oil immersioi 
The 400 interphase cells/had an average of 13.9 + 0.1 
faces, the range being from 9 to 21. There were 101 cells 
with 14 faces; 13- and 15ifaceted cells were also abun¬ 
dant. Hexagonal, pentagonal, and quadrilateral faces were 
most frequent. These 400 teells occurred in 96 combina¬ 
tions of faces; 38 cells had 4 quadrilateral, 4 pentagonal, 
and 6 hexagonal faces—the commonest combination— 
while four had 6 quadrilateral and 8 hexagonal faces, as 
in Kelvin’s tetrakaidecahedra. 
The 400 dividing cells averaged 16.8 + 0.1 faces, the 
range extending from 13 to 22. In these cells there were 
.170 combinations of faces, and pentagonal faces were the 
most numerous. Cells in early propliase had an average 
of 16.4 + 0.2 faces; in late prophase, of 16.7 ±0.3 faces: 
10 
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