H. DAVIS ON THE SO-CALLED DESICCATION OF ROTIFERS. 233 



coated, were similarly able to bear its action without injury. But 

 of course there was no certainty — only a strong probability — that 

 they were so coated: 



It is not quite so clear how a dry gelatinous shell would be pro- 

 tective against heat, although it would be far better than the 

 suggested porous dirt or sand ; still, as experiments show that 

 any temperature much above 200° both dries and kills the Rotifers, 

 such a shell may be considered protective so far. Other creatures 

 (even man himself in modellers' ovens for example) have been known 

 to bear extremely high temperatures without much inconvenience. 



There is no room for complaint as to the reception of my theory. 

 The fifth and subsequent editions of Dr. Carpenter's book accepted 

 it, Drs. Drysdale and Dallinger immediately adopted and adapted 

 it to their Bacteria germs, and a micro-biologist of note found a 

 good sounding name for the process, — " encapsulation." 



But there was always a difficulty in proving that the living 

 externally-dried Rotifers were encapsuled. I devised a sort of stage 

 trap-tank, with a shelf inside, to induce them when active to dry 

 apart from the dirt, &c. ; this with partial success, as single dry 

 specimens were sometimes found apparently gummed to the glass. 



Dr. Hudson, writing in 1873, said : — " Mr. Davis's solution of 

 a much-vexed question is as probable as it is new, and although it 

 may possibly require confirmation from future observers, I have 

 little doubt that such confirmation it will receive." Well, after 

 twelve years, the confirmation has come at last. The Rev. Edward J. 

 Holloway, of Clehonger, has found enormous numbers of P. roseolce 

 in the rain gutters of his church, and the very happy thought 

 occurred to him of placing some strips of paper in these gutters in 

 the rainy season, with a view to obtaining some clear gatherings of 

 the Rotifers when they had dried. He was entirely successful. Dry 

 groups in hundreds were taken. They have a varnish-like coating 

 all over, and are distinctly glued together — mostly in one plane — 

 and to the paper. 



Examples are on the table under the microscope, some dry living 

 groups on paper, and some in water taken this afternoon from the 

 same paper. Writing of these, Dr. Hudson says : — "Mr. Hollo- 

 way's beautiful groups prove your case beyond a shadow of a doubt. 

 I have a whole pavement of Philodines glued together ; moreover, 

 transparent prolongations of the gelatinous secretion may be seen 

 stretching from one to another." 



