OF ARTS AND SCIENCES. 207 



Mr. H. J. Clark made the following remarks on apparent 

 equivocal generation. 



"At the close of our last social meeting I was asked if I had seea 

 any trace of organization in the globules of the Vibrio-like fibrillte of 

 the muscle of Sagitta. My answer was in the negative. No longer 

 ago than yesterday I was fortunate in discovering the origin of another 

 form, or rather of several forms, of these pseudo-animate bodies, called 

 Infusoria. Whilst watching the decomposition of the inner wall of the 

 proboscis of a young Aurelia Jlavidula, our common jelly-fish, I ob- 

 served that the whole component mass of cells was in violent agitation, 

 each cell danced zigzag about within the plane of the wall. If any 

 one will shake about a single layer of shot in a flat pan, he can obtain 

 an approximate idea of the appearance of this moving mass. In a 

 perfectly healthy condition these cells lie closely side by side, and do 

 not move individually from place to place, but yet are active on one 

 side, which constitutes the surface of the stomach, where they are 

 covered by vibratile ciliae. As the young Aurelia grows, this wall 

 becomes separated from the outer one, but not completely, for the cells 

 of the two adhere to each other by elongated processes, varying in 

 number from one to six or seven. Each cell of the inner wall con- 

 tains numerous red or brown granules, a few transparent globules, and 

 a siiigle large, clear mesoblast. 



" When decomposition ensued, these cells became still further sepa- 

 rated from each other, and danced about in the manner which I have 

 just described. The vibratile cilias were not observed to share in this 

 movement ; in fact, I could not detect their presence, because, no 

 doubt, they had become decomposed and fallen away ; but the elongated 

 processes, which heretofore had remained immovable and stiff, lashed 

 about with very marked effect upon the cells to which they belonged, 

 and caused them to change place constantly. At last the inner 

 wall fell to pieces, and every cell moved independently and in any 

 direction. If at this time they were placed before the eyes of Ehren- 

 berg, or any one of his adherents, he would at once pronounce every 

 cell with a single process a Monas ; the red or brown granules would 

 be recognized as the stomachs filled with food, the transparent globules 

 as the empty stomachs, and the large mesoblast as the genital organ, 

 or propagative apparatus. Those with two processes would be to him 

 a CMlomonas, or some other genus closely related to it ; those with 



