58 RIcHARDS AND MacDouGaL: INFLUENCE OF | 
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the chemicals used were of the purest form obtainable, it was 
not thought advisable to trust to the product being free from 
impurities. Of course in preparing CO from oxalic acid it was 
necessary to wash out the CO,, which may easily be done, but in 
addition to this in all but the preliminary experiments the gas 
was passed over potassium permanganate, mercuric chloride, ete 
The analyses of gases produced by both methods showed the 
presence of no impurity except a small portion of atmospheric ait, 
which varied from 1.3 per cent. to 9 per cent. according to the 
method of preparation and the setting up of the experiment. The 
illuminating gas used was taken directly from the mains at Barnard 
College and at the New York Botanical Garden. No thorough 
analysis of this mixture was made, but the tests applied showell 
the presence of an amount of carbon monoxide not far from 40 
per cent. of the total volume. 
A small number of tests were made upon germinating seed- 
lings and it was found that a proportion of go per cent. or higher 
of carbon monoxide in the air around the seeds prevented all 
action of swollen seeds except in the pea, which succeeded in 
making roots less than a centimeter in length, and ultimately 
killed all the seeds. A smaller proportion of the illuminating g4° 
mixture was found to be inhibitory and fatal. Swollen seedlings 
of several species germinated in atmospheres containing about 7° 
per cent. of carbon monoxide, but the consequent growth and 
development was restricted. 
The results obtained from the exposure of seedlings germinated 
in the usual manner gave many facts of great interest and signifi 
cance. The seeds were placed in moist sphagnum and allowed? 
remain until the seedlings began to free themselves from the seed- 
coats, in short until the seedling reached a period of rapid growth 
when there would be likelihood of quick reactions to abnormal 
conditions. Glass vessels, varying in size according to the size of 
the seedlings, were then taken and after the flower-pots had bee? 
properly arranged in them, the air was completely replaced with 
water, after which a mixture of the gases desired was run in 
displace the water, except for a water seal at the bottom. In thé 
water some potash was placed, to absorb the CO, given off, great 
care being taken to have the flower-pot containing the seedling® 
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