v- V Li- JL.* 
charide contained glucose and galactose, as indicated 
chromatographically, with a smaller quantity of liexos- 
amine, probably N-acetylated, since the infrared spectrum 
showed absorption peaks at 1644 ancl/1560 cm -1 . 
The type-XIY substance, hitherto believed to contain 
only galactose and N-acetylgluco^ainine, both of which 
also occur in the cross-reacting Wood group substances, 
was found to be more comple/. Chromatographic and 
ionophoretic tests showed that glucose and glutamic acid 
appeared on vigorous hydrolysis. These were possibly de¬ 
rived from products with the/nobilities of di- and oligo¬ 
saccharides which were evid/nt on milder hydrolysis. In 
the infrared spectrum absence of absorption around 840 
cm 1 and the presence of a peak at 890 cm -1 indicated that 
the majority of the linkages were of the (3-type. 
Venezuelan Guay ana—a Long-Known 
but Little-Understood Region 
Charles B. Hitchcock, 
American Geographical Society , New York. 
Belief by Spanish explorers and adventurers of the mid- 
16th century in the legend of the fabulous and gold-rich 
city of Manoa in the interior of Venezuelan Guiana led 
to a burst of interest in the region, culminating in Sir 
Walter Raleigh’s ill-fated attempt to discover El Dorado. 
Major errors in the concept of the geography of the re¬ 
gion at that time are briefly outlined. Not until Alexander 
von Humboldt’s travels in the beginning of the 19th cen¬ 
tury was there a scientific evaluation of some of the geo¬ 
graphic realities. During the past 20 years, the efforts of 
the Venezuelan Government and such individuals as the 
explorer, Felix Cardona, and the ornithologists, William 
H. Phelps and William H. Phelps, Jr., as well as the ad¬ 
vent of air photography, have given an impetus to our 
understanding of the region, many parts of which still 
remain virtually unknown. 
Cartographically it has been one of the most puzzling 
areas in South America. The American Geographical So¬ 
ciety, in its program for preparing a uniform map of 
the Americas south of the Rio Grande on the scale of 
1: 1,000,000 was thrice forced to recompile Guiana before 
publishing because of new and conflicting information. It 
prepared a reconnaissance map of 16,000 mi- from air 
photographs in New York in connection with one of 
Phelps’ ornithological expeditions, thus providing the map 
from which scientific exploration of the virtually unknown 
could be planned beforehand. 
Of particular interest are those isolated mountains ris¬ 
ing into the subtropical zone, for there extreme endemism 
is exhibited by both plants and birds. The nature and ori¬ 
gin of the mountains, remnants of a once widespread 
sandstone formation, is discussed briefly. 
Studies on Animal Virus Reproduction 
Frank L. Horsfall, Jr., 
Rockefeller Institute for Medical Research 
Influenza A and B virus particles can be enumerated 
by determining the number of erytl/ocytes they cause to 
sediment at an increased rate. Becn/ise one infective par¬ 
ticle can initiate reproduction iiy susceptible cells, the 
ratio of infective to total particles can be found by deter¬ 
mining the smallest number of particles that can infect. 
The number of cells lining the allantoic sac of the 
chick embryo has been shown to be 1.8 x 10 7 . When less 
than one particle per cell of influenza A or B virus is 
inoculated, about 6 x 10 10 new particles are produced. If 
all cells support virus reproduction, the yield per cell is 
approximately 3 X 10 3 particles. 
With inocula of less than one particle per cell all the 
new particles of either virus are infective and the loga¬ 
rithmic rate of production is constant until the number 
of particles reaches about 90 per cell. Then the rate di¬ 
minishes sharply with increasing time, and noninfective 
particles accumulate rapidly. The time to double the 
number of particles is 46 min with influenza A, 60 min 
with influenza B virus. Both viruses lose infectivity at 
a rapid rate. In allantoic fluid at 35 °C the half-life of 
infective particles is 147 min for influenza A, 85 min for 
influenza B virus. Thus the ratios between generation 
time and half-life are as high as 0.31 and 0.71, respec¬ 
tively. 
Infective or noninfective particles of either virus in 
amounts greater than two per cell alter the reproductive 
process in three ways: (i) The interval before new par¬ 
ticles appear is increased, (ii) The logarithmic rate of 
production is decreased, (iii) The proportion of new par¬ 
ticles that are infective is markedly diminished in direct 
relation to the initial particle-cell ratio. 
In contrast, infective Newcastle disease virus has a 
half-life greater than 14 hr A 35 °C and a generation 
time of 43 min. Thus the generation time-half-life ratio 
is less than 0.05. The yield par cell is about 1 x 10 s par¬ 
ticles. Unlike influenza, Newcastle disease virus in 
amounts greater than two particles per cell does not alter 
the reproductive process. Regardless of the particle-cell 
ratio, all new particles produced are infective. 
/ . 
Effect of Chemicals on Sporulation of Fungi 
James G. Horsfall and Saul Rich, 
Connecticut Agricultural Experiment Station 
The process of asexual sporulation in fungi is only 
vaguely understood. It necessitates cell division and a new 
cell wall that is distinct jso that the spore can be pinched 
off. It requires extra energy above that needed for vege¬ 
tation. Sporulation is induced by an optimum energy 
level that varies among fungi. Metals are known to aug¬ 
ment sporulation. Tha following classes of compounds 
generally reduced sporulation of Monilinia fructicola in 
pure culture on agar: chelating reagents, ketones, thiones, 
amines, phenols, hydrocarbons, and chlorinated hydro¬ 
carbons. The effect of ketones and thiones is quenched by 
a basic nitrogen group nearby on the molecule, and vice 
versa. «, (3-Unsaturhtion of a ketone usually enhances 
biological activity. Here it seems to quench activity. 
We suggest that Chelating agents bind metals that par¬ 
ticipate in energy-giving oxidative reactions, that ketones 
and thiones lift the redox potential above the optimum 
for sporulation and the amines push the potential below 
the optimum, that they cancel each other when present 
on the same molecule, that mitosis is discouraged (i) by 
reaction of the ketones, thiones, amines, and phenols with 
the proteins of the chromosomes, and (ii) by interference 
with spindle-fiber formation by hydrocarbons and chlorin¬ 
ated hydrocarbons. We suggest further that fission of bac¬ 
teria and sporulation of fungi may be biochemically re¬ 
lated, because metal starvation, phenols, and certain 
amino compounds are known to retard fission of certain 
bacteria. 
7 
