522 THE NATURAL HISTORY OF 



broader, greener, reddish band containing the motile 

 individuals. The motions of the various forms oiIice)iia- 

 tococcus are then described, (p. 623,) and, from tlie 

 description, appear to be very like those of 'Eur/lena 

 viridis. In fact so cmch so that Flotow himself com- 

 pares them with those of Astasia pluvialis, deeming, 

 hovi^ever, that species, vi^hich is either identical with, or 

 closely allied to Eufjlena, as an animal Infusorium. He 

 goes on to say, however, " that there is no appearance, 

 in the Hamatococcus, of animal organisation, particularly 

 of a mouth, intestine, or stomach ; nor is the admission 

 of indigo into the interior ever observed." 



Flotow considers that the source of the motion of the 

 globules of Hamatococcus is quite problematical. 



Having thus premised an abstract of the more impor- 

 tant points in Plotow's researches, from which the above 

 are extracts, the author proceeds to detail his own obser- 

 vations, which he says are to be considered only as 

 supplementary, in a great measure, to those of Flotow, 

 which he regards as of the highest value. 



On the 2d January, 1850, some particles of sand 

 coxiisanmgProtococciis phwialisvi\\\ck had been collected 

 by A. Braun, were placed in a deep glass vessel and 

 covered with snow-water. The first moving forms were 

 noticed on the 8tli of January. The Protococcus had 

 been in a dry state in the herbarium for two years. 

 Other experiments showed that this retention of vitality 

 endured through many years. 



In his experiments the author found great convenience 

 in the employment of little glass vessels in the form of a 

 truncated cone, about two inches deep and one inch and 

 a quarter in diameter, with a flat bottom polished on 

 both sides. These little vessels were filled with water to 

 the height of two to three lines. It was only in vessels 

 of this kind that he was able to follow the development 

 of a number of various cells throughout its whole course. 

 Although he agrees in the main with the views expressed 



