308 PHYSIOLOGICAL BOTANY. 



describes, with great care and accuracy, the transforma- 

 tions of a small Alga, or a small Infusorium, Hcematococcus 

 pluvialis, into the most varied forms. A red matter was 

 first found in the rain-water from a surface of granite 

 (at Hirschberg) ; this consisted of extremely delicate 

 globular, shining vesicles, filled with a mass which, in its 

 moist state, was granular, and of a carmine red colour ; 

 when dried upon paper, it was of a vermilion red colour. 

 These granules not only experienced a change of colour, 

 becoming greenish after some time, but at the end of 

 September and the commencement of October, move- 

 ments commenced in the granules. These consisted of 

 1, Motion in the direction of a curve (longitudinal mo- 

 tion) ; 2, Rising and sinking in serpentine lines ; 3, A 

 rotatory motion. Water removed from the above cavity 

 was then examined from time to time, and the altered 

 forms studied, examined, and described with extraordinary 

 accuracy. On the 30th of November filaments began to 

 be formed ; on the 13th of December he examined some 

 of the rain-water which had been taken on the 9th of 

 October, and subsequently kept in a warm room; he 

 then found an infusorium, Astasia pluvialis, in it, which 

 is nearly related to A. nivalis Shuttlew. I cannot dispel 

 the idea, says he, that this Astasia arose from the Haema- 

 tococcus, and that it is only a higher stage of development. 

 Its agreement in form and contents with the Hteinato- 

 coccus globules themselves, the number of intermediate 

 forms, composed of perfectly round figures, which from 

 the first become slightly oval or ovale, afterwards more 

 and more so, and sometimes are free from tubercles, 

 at others bear them, almost entirely preclude the for- 

 mation of an absolute line of demarcation between the 

 phytonomic or infusorial animated individuals. This 

 Astasia pluvialis is not seen to be produced in any kinds 

 of infusion which do not contain Htematococcus pluvialis, 

 the presence of which is a necessary condition to its for- 

 mation. Moreover, a constant reciprocity is observed to 

 exist between the two ; the Astasite increase by sub- 



