392 



GENERAL PHYSIOLOGY 



De Bary ('87), in his lectures upon Bacteria, has collected a 

 number of similar examples from the life of these organisms. In- 

 vestigations of other objects, such as animal egg-cells, leucocytes, 

 etc., would supposably give wholly analogous results. 



But the excitation-effects upon the phenomena of changes of energy, 

 especially upon motion, are most directly noticeable. Here, also, 

 in general, an increase of motion accompanies increasing tem- 

 perature. In following these phenomena in single living cells, the 

 warm stage devised by Max Schultze for this purpose can best be 

 employed. It consists of a horseshoe-shaped brass plate, widened out 

 at its curved part so as to cover a greater surface (Fig. 181). 

 Under this surface, which is pierced by a diaphragm, there is a 



FIG. 181. Warm stage. (After Max Schultze. 



thermometer spirally wound, the upper end of which projects upon 

 a scale between the two limbs of the horseshoe-shaped stage. The 

 whole is fastened upon the stage of the microscope, and beneath 

 the two ends of the horse-shoe spirit-lamps are placed, which slowly 

 heat the stage. With the thermometer the height of the 

 temperature prevailing in the middle of the stage can easily be 

 controlled. 



In this way it can be demonstrated that the protoplasmic move- 

 ment of Amoeba, as Engelmann ('79, 1) found, is always more active 

 with increasing temperature and that, as Kiihne ('64) first 

 established, these Protista fall into strong contractions at 35 C., as- 

 suming a spherical form, just as after strong chemical or mechani- 

 cal stimulation (Cf. Fig. 183, B, p. 395). Other rhizopods such as 

 Actinusphcerium , Orbitolites, etc. (Cf. Figs. 179 and 180), as 



