ANIMALS AND PLANTS. 133 



from which they emerged ; I say that in spite of this strong hint, 

 it was not until Ehrenberg had excited the marvel of the scientific 

 world by his disclosures of the complicated organisms of many 

 of these moving atoms, and had stirred up a lively and some- 

 times rather too caustic criticism upon the correctness of his 

 observations, and by this means had brought the microscope into 

 use as a scientific instrument, whose tremendous power as an 

 engine of progress, along the great road of science, I believe is 

 but half suspected, not until Ehrenberg had given this impulse, 

 and there finally appeared in the field a class of observers who 

 devoted themselves to the elucidation of the nature and relation 

 of the so-called Infusorial animalcules, that it was suspected 

 that anything but animals were comprised in this group. 



Finally, from the year 1843 to 1850, among other observers, 

 Thuret was the most active in throwing doubts upon the an- 

 imality of certain of the so-called Infusoria, which were classed 

 together from their similarity^ as here represented (figs. 67 to 72). 



Fig. 69. 



Fig. 67. 



Fig. 67. Protococcus pluvialis. A zoospore. 1000 diam. c, cell-wall; g, 

 granular contents ; e, transparent region ; n, nucleus ; , , vibrating lashes. 

 Original. 



Fig. 68. Saprolegna ferax, in different stages of growth. 500 diam. n 1 , 

 body of the zoospore ; I, vibrating lash of the same ; n, n~, p, three successive 

 degrees of development. Original. 



Fig. 69. Chlamidomonas pallida, n. sp. 500 diam. c, the pair of contrac- 

 tile vesicles. Original. 



