May 8, 1896.] 



SCIENCE. 



691 



ilar to those resulting from the use of con- 

 centrated nutritive solutions. If such struc- 

 tures were brought into atmospheric air 

 vegetative mycelise were formed. Spores 

 which had been immersed in pure CO^ for 

 three months germinated in the usual man- 

 ner. In confirmation of Brefeld's work, 

 Lopriore finds that Saccharomyces will not 

 grow in pure CO,, although but one-six 

 thousandth part of oxygen is necessary as 

 has been found by Brefeld. After 12 hours' 

 immersion in the pure gas growth was re- 

 sumed upon access of atmospheric air. 

 Mixtures containing large proportions of 

 CO, exerted a much stronger adverse influ- 

 ence upon Mycoderma cerevisise, which was 

 killed by twelve hours' exposure to the pure 

 gas. 



Pollen gi-ains reacted to mixtures in the 

 most varied manner. Some formed protu- 

 berances in the pure gas, and then burst; in 

 others no change was visible, while in others 

 disintegration shortly ensued. Tubes formed 

 in air and exposed to pure CO, were gener- 

 ally quickly destroyed. Proportions of 1 

 to 10 parts of CO, promoted the growth of 

 the tubes, but did not increase the turgidity, 

 which, however, was markedly increased if 

 afterward brought into ordinary air. It 

 will be remembered that in pollen tubes 

 growth-extension of the walls is practically 

 independent of turgidity. In many in- 

 stances important changes in the plastic 

 and elastic extensibility of the cell wall 

 were induced, in a manner similar to the 

 effects of strong oxygen solutions. 



The results of Lopriore's work point to 

 the conclusion that CO, exercises a retard- 

 ing influence upon the activity of proto- 

 plasm, while directly exposed to it, but has 

 no permanently injurious effect. Different 

 plant cells exhibit widely divergent reac- 

 tions to the gas. It appears quite well es- 

 tablished that animal protoplasm is affected 

 much more strongly by increased propor- 

 tions of the gas. The influence of the gas 



upon the protoplasm of plant cells is charac- 

 teristic, and its efiects do not result from 

 the simple exclusion of oxygen ; its action 

 is upon the nutritive processes, and since 

 the widest disproportion exists between the 

 yolume and the effect produced, if it exer- 

 cises any stimulating influence the reaction 

 must be so limited as to be easily obscured. 



The establishment of the fact that CO, 

 exercises a positive influence upon- proto- 

 plasm makes necessary a revision of some 

 of the conclusions reached concerning aerobic 

 and angerobic organisms, and particularly 

 the researches of Correns (Ftora, 1892) upon 

 the relations of plants to oxygen, in which 

 oxygen was partly or entirely displaced by 

 CO,. The anomalous reactions of tendrils 

 obtained by this author seem to be capable 

 of explanation in view of the recently dis- 

 covered relations of the gas to plant proto- 

 plasm. D. T. MacDodgal. 



The State Univeesity of Minnesota. 



NOTES ON CERTAIN VNDESCBIBED CLAY OC- 

 CURRENCES IN MISSOURI 



The geologically well-known clays of the 

 State of Missouri (which are very abundant 

 and widely known, commercially), occur 

 in the Quaternary — chiefly confined to the 

 loess deposits along the larger rivers; in 

 the Tertiary — in the southeastern part of the 

 State ; and in the Coal Measure formations 

 — in the extension of the Iowa Coal Basin 

 southwestwardly, and also in the small out- 

 lier of the Illinois Coal Basin, which is con- 

 fined, practically, to St. Louis city and 

 county. 



Another interesting and commercially 

 valuable group of clays, which has, appar- 

 ently, never been described, includes a large 

 number of more or less isolated pockets of 

 fire clay and 'kaolin,' occurring uncon- 

 formably in cavities and former valleys 

 among the Silurian and, possibly, in some 

 Devonian and Lower Carboniferous rocks. 

 These pockets of clay are distributed over 



