ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 559 



teids); (2) for the formation of cellulose; (3) for the liberation of 

 energy by respiration, nutrition, and growth. The enzymes formed by 

 the lower plants are also useful in more than one way, not the least 

 important use being the conversion of irrespirable into respirable sub- 

 stances. 



The sulphur bacteria (Beggiatoa, Chromatium, &c.) obtain most, if 

 not all, of their kinetic energy by oxidising sulphur compounds. Such 

 bacteria as Crenothrix, which live in water rich in iron, obtain their 

 kinetic energy by oxidising ferrous compounds. 



Respiration of Dormant Seeds. * — In the case of Hordeum dis- 

 tichum, R. Kolkwitz finds the amount of carbon dioxide given off to 

 depend to a remarkable extent on the moisture of the atmosphere. 

 When air-dried the grains contain from 11 to 12 p.c. of water, and the 

 amount of C0 2 then given off does not exceed ■ 33-1 ■ 5 mgrm. per kgrm. 

 per hour. With an increase of moisture in the air the respiration in- 

 creases very rapidly in intensity, until, when it has reached 33 p.c, the 

 amount of C0 2 given off has mounted to 2000 mgrm. per kgrm. per hour. 

 Even when cut into small pieces or crushed, tbe power of respiration is 

 not altogether lost. The vitality of dormant protoplasm must be even 

 greater than has hitherto been supposed. 



Respiration of the Olive, f — C. Gerber has made a series of observa- 



CO 



tions on the value of the respiratory quotient -^ in the formation of 



oil in the olive. The ripening of the olive may be divided into three 

 periods : — during the first period the fruit contains mannite which has 

 been transferred from the leaves, and the respiratory quotient is less 

 than unity, about ■ 92. During the second period, in which the colour 

 of the olive changes from green to violet, the mannite is partially 

 oxidised, and the value of the quotient rises to 1*40. It is during this 

 period that the greatest production of oil takes place. During the 

 third period, in which the colour of the fruit changes from violet to 

 black, a further production of oil is effected at the expense of the 

 remaining mannite and other carbohydrates, and this is accompanied by 

 a gradual decrease in the respiratory quotient, until it again becomes 

 less than unity. 



Combined Action of Diastase and Yeast on Starch-Granules.f — 

 G. H. Morris has shown that when certain ungelatinised starch-granules 

 are submitted to the joint action of malt extract and yeast, the quantity 

 of starch decomposed by the joint action is about three times that dis- 

 solved by malt extract alone. The combined action occurs only with 

 those starches which are attacked in the ungelatinised form by diastase, 

 such as barley or malt starch. The granules of potato starch are not 

 acted on by diastase even in the presence of yeast. 



y. General. 

 Production of New Forms.§ — Prof. R. v. Wettstein sums up the 

 state of our knowledge as to the fresh formation of forms in the vege- 



* Ber. Deutsch. Bot. Ges., xix. (1901) pp. 285-7. 



t Journ. de Bot. (Morot), xv. (1901) pp. 9-22, 88-94, 121-36. 



X Proc. Chem. Soc, xvii. (1901) p. 178. 



§ Ber. Deutdch. Bot. Ges., xviii. (1900) Gen.-Vers.-Heft, pp. 184-200. 



