52 



GENERAL HISTOBY OF 



But the doubt may arise, whether the being Weisse observed "vras 

 the true animal CMorogonmn, or only a thecaspore or zoospore of 

 an Algae (see Thuret's Essay, before quoted), a production so similar 

 to the green-coloured Infusoria, that we have really no means of 

 distinguishing bet^yeen tlie two, and, what is more, a production 

 which is known to develop e by the fission of its endochrome or gi-een 

 contents. 



Not only did Ehrenberg discover a testis in the nucleus of Poly- 

 gmtrica, but conjectured the pulsating sacs and their prolongations, 

 existing in all those with a mouth, and in some others, to represent 

 a spennatic sac with vas-deferens and vesiculoe seminales. But the 

 majority of obser\-ers would rather consider them as the fii'st 

 rudiments of a circulatory system ; and we shall defer any further 

 mention of them till that system is considered in a following section. 



Before dismissing the subject of the propagation of Infusoria, it is 

 right to notice some recent researches of M. Pineau (Annales des 

 Sciences NatureUes, vol. III. 3rd series, 1845, and vol. IX., 1848), 

 in which he endeavours to prove the transformation of organic 

 matter into definite organic beings, and that there is a perfect 

 analogy between the production of cells in general, and that of 

 animalcules, and of microscopic infiisory plants. Moreover, he would 

 extend the phenomenon of transformation to the organised beings 

 when developed. 



Thus he states, that in an infusion of different plants, the first 

 index of the progress of organization was a granular mass, sub- 

 dividing into granular globules. Of these, some of the more 

 advanced presented diverging, but motionless processes; in others 

 more isolated, those appendages exhibited an oscillatory movement, 

 and in them he identified a species of Actinophrys. At first, the 

 radiating expansions were all alike, but in the progress of develop- 

 ment, one was observed to affix itself to a neighbouring body, and to 

 outgi'ow the rest. In this form he recognized the Actinophrys 

 pedicellata (Dujardin). 



He next describes the appearance of a pjTifonn animalcule seated 

 on a non-contractile stalk, with the trace of a circular orifice, which 

 he believed might be assigned to the genus Amieta, whilst the 

 succeeding phase of evolution exhibited perfect Vorticella. 



