214 THE PHENOMENON OF 



against it, since the red colour does not always present 

 the drop-form peculiar to oil. In completely red resting- 

 cells the entire contents (with the exception of the starch- 

 vesicle) appear saturated with the red colour, no separate 

 red drops being distinguishable ; but I sometimes found 

 in the dishes of water in which I cultivated the Chlami- 

 dococcus, resting- cells (diseased ?) in which the brownish- 

 green contents were somewhat retracted from the tough 

 cell-membrane, and between the membrane and contents 

 long flattened drops of decidedly oily aspect and dark 

 yellowish-red colour had been formed. The connected 

 red nucleus, such as occurs especially in the active cells, 

 readily breaks up into many oil-like drops, as, for 

 instance, when diseased cells decay in water, as also 

 when they die from being dried up ;* when the cell is 

 crushed ; as also, lastly, when sulphuric acid is applied, 

 which moreover gradually gives the red drops a dirty violet 

 colour. Oil of turpentine, on the contrary, in recently 

 dried-iip cells, spreads the red colour uniformly through 

 the whole contents, or in a greater abundance at the 

 circumference of the cell. 



The formation of oil presents itself with greater clear- 

 ness in the sleeping state of Chlaviidomonas. Several 

 species of this genus, hitherto included in the Animal 

 kingdom, but nearly allied to Gloeococcus and Cfdamido- 

 coccus, present themselves in the beginning of spring, in 

 such abundance that they produce a striking green 

 coloration of the water ; a few weeks later they vanish, 

 leaving no trace, and are not noticed again throughout 

 the whole year. I have observed the circumstances 

 attending this disappearance in a species which I call 

 CJdamidomonas ohtusa.\ I brought this home in the 



* According to my observations, all active forms die when dried up. I 

 cannot confirm the existence of a Hamatococcus jduvialis atomarim, such as 

 Von Plotow thinks we may believe in. The preservation of Chamidococcus, 

 both in the dry and frozen state, certainly occurs only through the resting, 

 thick-walled form. 



t Chlamidomonas (a name certainly sounding strangely in the vegetable 

 kingdom) is distinguished from the genus Chlamidoooccus by the closely 



