524 BXPEEIMENT STATION RECORD. [Vol.41 



fact that as plants abstract carbon dioxid from a solution the latter becomes 

 more alkaUne. IMiuiite amounts of photosynthesis in marine plants can be 

 measured accurately by adding a little plienolphthalein to the sea water and 

 observing the color changes. By this method it was found that Ulva after 

 being kept in darkness begins photosynthesis as soon as it is exposed to sun- 

 light, and the rate steadily increases to a constant value, 



A method of studying respiration, W. J. V. Osterhout (Jour. Gen. Physiol., 

 1 {1918), No. 1, pp. 17-22, fig. 1). — Apparatus is described by which small 

 amounts of carbon dioxid given ofi: by organisms can be measured rapidly cind 

 accurately. The apparatus can be employed also to measure photosynthesis. 



An indicator method of measuring the consumption of oxygen, W. J. V. 

 Osterhout {.lour. Gen. Phyuol, 1 {1018), No. 2, pp. 167-160 ) .—The author de- 

 scribes a method of measuring oxygen consumption employing the blood of the 

 horseshoe crab {Limulus sp.). This absorbs oxygen and turns blue when shaken 

 in air, but is quickly decolorized in the presence of certain organisms which 

 consume oxygen. By measuring the time required for the change of color the 

 rate of consumption of oxygen (by animal or plant) may be determined. 

 This method is employed in some of the series below. 



Comparative studies on respiration, I-V {Jour. Gen. Physiol, 1 {1918), No. 

 2, pp. 171-220, figs. 17). — Fi\e papers are presented. 



I. Introdiictioii, W. J. V. Osterhout (pp. 171-179). — The author describes the 

 first of a series of investigations on respiration in plants (which is in some 

 cases compared with that of animals), employing infproved quantitative 

 methods dealing with representatives of bacteria, higher fungi, algse, and 

 flowering plants. It is shown that when anesthetics are employed in sufficient 

 concentration to produce any result, plants show a rise in the rate of respira- 

 tion followed by a decline. In animals the rise (found in higher concentra- 

 tions only) was preceded by a temporary fall not entirely due to lowering of 

 muscular activity or tonus. In lower concentrations the effect was merely a 

 decrease of respiration. The results of aU the investigations are opposed to 

 the theory of Verworn, namely, that anesthesia is a kind of asphyxia due to 

 the checking of respiration by the anesthetic. 



II. The effect of anesthetics and other substances on the respiration of 

 Aspergillus niger, F. G. Gustafson (pp. 181-191. — In this investigation, which 

 was undertaken to compare the action of anesthetics and other substances on 

 the i-espiration of a fungus {A. nigcr) with effects produced in other groups 

 of organisnfs, it was found that in effective concentrations formaldehyde, 

 ether, and acetone first increased and later decreased the rate of respiration. 

 Ether at 3.65 per cent caused an increase with certain cultures, a decrease 

 with others. The reaction producing an increase in the respiration with 7.3 

 per cent ether is reversible, the reaction producing the decrease irreversible. 

 Caffein at 0.5 per cent produced only a decrease in respiration. A saturated 

 solution caused an increase, which was followed by a decrease. 



III. The effect of ether on the respiration and groicth of Bacillus subtilis, 

 M. M. Brooks (pp. 193-201). — It was found that all concentrations of ether 

 employed (from 0.037 to 7.3 per cent) caused an increase in the rate of respira- 

 tion of B. subtilis, followed by a decrease. Ether at 7.3 per cent in tap water 

 gave an extraordinary increase (50 times the normal) in the output of carbon 

 dioxid. This increase did not occur when 0.85 per cent sodium chlorid was 

 added. At lower concentrations (0.037 to 1.1 per cent) ether was toxic, and 

 the same was true at higher concentrations (3.65 to 7.3 per cent), while in- 

 termediate concentrations stimulated growth. 



IV. The effect of ether on the respiration of icheat, H. S. Thomas (pp. 203- 

 207).— The experiments here described show that 7.3 to 3.65 per cent ether 



