690 



SCIENCE. 



[N. S. Vol. III. No. 71. 



panying the experiments he concluded that 

 the gas was poisonous to plants (1810). 

 About this time Davy obtained some results 

 confirmatory of those previously attained 

 by De Saussure. 



N"o further'important facts were brought 

 out until forty years later when, in the 

 period of activity following the discovery of 

 protoplasm, its relation to carbon dioxide 

 were taken up by Kabsch, in a study of its 

 influence on 'sensitive' plants (Bot. Ztg., 

 1862). The field attracted many workers 

 of the first rank among whom are Kiihne, 

 Boussingault, Pfefier, Schiitzenberger, God- 

 lewski, de Vries and Boehm, who paid chief 

 attention to the influence of the gas in vary- 

 ing pressure and proportion upon the syn- 

 thetic activity of chlorophyll-bearing plants. 

 The discovery of Pasteur that certain 

 forms of Saccharomycetes and Schizomycetes 

 might live in a medium devoid of oxygen, 

 M'as followed by the experiments of Frankel, 

 in which he found that many forms of 

 these groups might live in an atmosphere 

 of pure CO^, and that the I'elations of each 

 form to the gas was entirely specific (1889). 

 D'Arsonval, pursuing similar lines of experi- 

 ments, met no organism capable of con- 

 tinued existence in this gas at high 

 pressures, forty-five atmospheres (1891). 

 Frankland obtained results entirely in 

 harmony with those of Frankel and 

 further found not only great specific dif- 

 ferences in resistence to the gas, but 

 also wide difl'ererences in individuals 

 from the same colony (1889). Demoor in 

 some recent Avork upon the subject in con- 

 nection with the effects of manj^ dif- 

 ferent gases reaches the conclusion that the 

 activity of the plasma is possible only in 

 the presence of oxygen, while the nucleus 

 may not be affected bj' conditions which in- 

 hibit the action of the plasma.* Perhaps 

 the most extensive and exact series of ex- 

 periments dealing with the relations of CO^ 

 *Aroh. d. Biol., 13: 163. 1894. 



to protoplasm devoid of chlorophyll is that 

 recently carried out by Lopriori at Berlin.* 

 This writer used gas obtained by heating 

 potassium bicarbonate, according to the 

 method of Schloesing and Laurent, which 

 was stored in gasometers of special design, 

 and the integrity of all mixtures was con- 

 firmed by numerous analyses. The micro- 

 scopal examination was made in chambers 

 similar in principle to that of Engelmann. 

 Among his more important results are those 

 which concern the accommodation of pro- 

 toplasm to the unusual proportions of 

 the gas and the germination of spores un- 

 der such conditions. The streaming move- 

 ment in the stamen hairs of Tradescantia 

 was inhibited by exposure to a mixture of 

 20 parts oxygen and 80 parts CO, for 3 or 4 

 minutes, and was resumed after a minute's 

 exposure to the air. A second exposure to 

 the same mixture a half hour later had no 

 effect on the movement, and a. much greater 

 proportion of CO, was now necessary to in- 

 fluence the rate of movement. By immer- 

 sion of the hair in successive mixtures of 

 the following composition : 



1. 25 parts CO, 75 parts 



2. " 20 " " 80 " 



3. " 10 " " 90 " 



4. " " 100 " 



it was possible to maintain the movement 

 in the pure gas. 



The germination of spores of Mucromu- 

 eedo was totally inhibited in pure CO, and 

 delayed a varying length of time in mixtures 

 containing high proportions. The my- 

 celiiB formed in mixtures containing above 

 10-30 parts of CO, did not develop spo- 

 rangia. In such instances the protoplasm 

 became highly vacuolar, while globular 

 swellings were formed on the myceliaj sim- 



*Ueberdie Einwirkung der Kolilensiiure auf das 

 Protoplasma der lebeiiden Pflanzenzelle. Jabrb. f. 

 wiss. Bot. 28 : H£t. 4. 531-625. 3 Fige. 2 Pis 

 1894. 



