PHYSIOLOGICAL BOTANY. 309 



division, but their embryo in part again assumes the form 

 of Haematococcus. I must at least assume this to be the 

 case. Thus the author saw the Htematococcus increase 

 in vessels which were set aside, and attach itself to their 

 sides. He also perceived infusiorially-animated indi- 

 viduals among them ; but he never saw the Hcematococ- 

 cus, which was then at rest, subdivide. He separated 

 the Hcematococcus, and then found that every change of 

 temperature, or of the water, provided the latter was 

 pure, and the globules had acquired maturity, produced 

 an alteration in the H.pluvialis. Experiments detailed 

 with the same extreme minuteness follow the observations. 

 They were performed with infusions of Hamatococcus, 

 and contain a number of very remarkable observations 

 upon the various forms which this being produces ; but 

 we must refer the reader to the memoir itself. The 

 author is uncertain whether he should refer Htematococcus 

 to the animal or the vegetable kingdom, but concludes in 

 favour of the latter opinion. 



The same subject is treated in a shorter paper : On the 

 Conversion of Infusoria into the loiver Forms of the Algce. 

 By Dr. FR. TRAUG. KUTZING. Nordhausen, 1844, 4. 

 After some historical remarks, in which Flotow's memoir 

 is also quoted, the author communicates some observa- 

 tions, the result of which is, that Chlamidomonas pulvis- 

 culus is susceptible of numerous changes ; that a decided 

 species of Algae, Stygeoclonium stellare, is developed from 

 it, but that other formations also emanate from it, which 

 likewise decidedly have the characters of the Algae, 

 although from their external form they might in part lay 

 claim to being considered as infusorial forms in a state 

 of rest. 



In conclusion, says the author : " The natural history 

 of organisms has hitherto been treated of by two methods, 

 according as the object is considered as perfected, or in a 

 transient state. Linnaeus may be regarded as the dis- 

 coverer of the defining method in natural history, and 



