GENERAL PHYSIOLOGY 179 



only demonstrates the presence of a membrane in various types 

 (Paramecium caudatum, Lionotus folium, Nassula lateritia, Cam- 

 panella umbellaria and other VorticelUdae) but, by use of fixation 

 methods employed for demonstrating the Golgi apparatus in meta- 

 zoan cells, comes to the conclusion that the membrane of the con- 

 tractile vacuole is a part of the Golgi apparatus. This, in Metazoa, 

 he had earlier (Nassonov, 1923) identified as an organoid intimately 

 bound up with secretory activities of the cell (see also Bowen). In 

 different Protozoa the contractile vacuole, which he unhesitatingly 

 calls an excretory apparatus with a definite lipoid membrane, is 

 variously complicated, from a simple vesicle with osmiophilic mem- 

 brane in forms like Chilomonas paramecium (Fig. 95, B, p. 171), to 

 complex aggregations of vesicle and canals as in Paramecium (Fig. 

 95, A, C). In the latter case the canals appear to contain the ma- 

 terial by activity of which substances are chemically differentiated 

 for secretion and these are passed on to the vesicle 1 >y which they are 

 excreted. According to Nassonov the lipoid-containing membrane 

 (confirmed by Chatton, 1925, and by Gelei, 1928) must be semi- 

 permeable and its contents must have a higher osmotic pressure than 

 the surrounding plasm. Hence fluids would flow into the vacuole 

 completely distending it until the pressure would burst the retaining 

 membrane and the fluid would be ejected. The highly viscous 

 membrane would mend but for a new flow into the vacuole a new 

 supply of osmotically active stuff would be necessary. This, Nas- 

 sonov assumes, is formed by secretion from the osmiophilic mem- 

 brane into the canals and vacuole. This secreting activity is com- 

 pared with the secretory activity of the Golgi apparatus in Metazoa. 

 Gelei holds, however, that the function here is to condense and to 

 conduct concentrates from the plasm into the canals, not a secre- 

 tory function, but excretory. (See also Lynch, 1930.) With this 

 work of recent investigators we have a very definite argument for 

 the excretory functions of the contractile vacuole and for the pres- 

 ence and function of the lipoid membrane. In quite a modern way 

 it brings us dangerously near to an Ehrenbergian conception of a 

 kidney and bladder in Protozoa. 



C. Irritability. — In the absence of all knowledge as to the manner 

 in which protoplasmic particles respond to stimuli of different kinds, 

 we are constrained in speaking of irritability of Protozoa, to limit 

 descriptions to aggregates of such responses as manifested through 

 movement, as energy transformed by oxidation from the poten- 

 tial or stored chemical energy to the active or kinetic condition, or 

 as manifested by adaptations to changes in environment. But the 

 manner in which such kinetic energy is utilized in pseudopodia 

 formation or by the elements of rlagellum, cilium or myoneme, is 

 a matter of pure speculation. The reactions which characterize 

 the resulting movements, however, can be analyzed and measured 



