248 Actinospliaerium Eichornl 



half au Unit of the scjile, so that the process of averaging was only employed 

 to Cover small fluctuations. 



D. Au iucreased tcmperature hastens on encystmeut, a low teinperature 

 retards it. 



I have provcd the truth of this general statement by nutnerous instances but 

 I havt" not dctcrniincd the facts with the accnracy which the (;|uestion deserves. 

 The following rough observations unist at preseut suffice : — 



1. Individuais measuring 34"39 — 41 '63/4 wcre placed in the wann temperature 

 (24° — 26°C.) on Saturday evening 8th ; on following Wednesday afternoon, 12th, 

 conjugation cysts were formed in most cases. 



2. Similar culturc to abovo was set on 8th at room temperature (15° — 10° C); 

 encystment begau on 12th, conjugation cysts formed on 17th. 



3. Siuiilar culture to above placed in the cold tcmperature (7° — 12° C.) on 

 the 8th ; encystment began on 19th, conjugation cysts formed on 23rd. 



4. Culture at 24° — 26^ C. set on Saturday, all conjugated on following 

 Thursday. 



ö. Culture at 24' — 26^ C. set on Sunday, all conjugated following Saturday. 



G. Culture at 24°— 26° C. set on 23rd, all conjugated 30th. 



7. Culture placed in cold temperature (7° — 12° C.) from Nov. 23rd — Dec. 

 2nd. Put in warm Dec. 2nd, all conjugated Dec. 8th. 



8. Culture set at 7° — 12° C. on Dec. 2nd, conjugation cysts formed on 

 Dec. 16th. 



From thcse facts it may be concluded that in starvation cultures the time of 

 onset of encystment is directly dependent ou the temperature, being quiekest 

 in thi' luat, iutermediate at ro(jni temperatures, and much protracted in the cold. 



E. Au increased temperature causes fewer and larger cysts to be built, and 

 vice versa. 



The readir niust refer to Tablf IV. Herc I havc tabulated the correlation 

 between the number of cysts and the size of cysts at 24° — 26° C. with thin Arabic 

 figures, while the Arabic tigures in brackets refer to creatures that encysted in 

 the cold 7° — 12° C. It will be seen that the majority of the Arabic figures fall 

 in the lower left-hand quarter of the table, i.e. the ([uartor referring to few and 

 large cysts, while the tigiu-es in brackets fall in the upper right-hand corner, the 

 quarter refcrring to numerous and small cysts. The figures in Table III. would 

 form a kind of bridge between the two series in Table IV. The somewhat wide 

 deviation from the mean exhibiled by certain individuals that encysted at a high 

 teinperature suggests further problems : but the small number of instances do not 

 pennit of generalization. 



