CORRESPONDENCE. 287 



To the Editor of the ' Monthly Microscopical Journal? 



Sir, — When Mr. Slack, at the April meeting of the Koyal Micro- 

 scopical Society, promised to furnish evidence to justify his mitigated 

 strictures and somewhat patronizing remarks on the supposed want of 

 originality in my paper on desiccation, a vague uneasiness was left in 

 my mind which, he may be pleased to hear, his letter at page 241 

 entirely dispels. 



His quotations only show that the most recent writers on the 

 subject go no further and prove no more than the older experimentists. 

 The ques'tion being — can rotifers survive desiccation? was neatly 

 " begged " by a method not altogether unknown to Mr. Slack,* for the 

 creatures being baked and air-pumped, were only admitted to be dry 

 when they did not revive, while, in the common event of the most 

 protracted desiccating arrangements failing to kill, the drying process 

 was pronounced imperfect. Pennetier, indeed, made a lame endeavour 

 to account for the rotifers' preservation, but his explanation, and that 

 a false one, had been anticipated by an anonymous English writer 

 in 1860.| 



Practically, Pouchet in 1859 closed the controversy so far, but 

 lacking the true explanation of the phenomenon (furnished for the first 

 time in my paper) only helped to a settlement of the question against 

 his own theory. It is incredible that if in 1859 or earlier it had been 

 proved or " settled " (as Mr. Slack affirms) that a perfectly dry rotifer 

 was destroyed, such an author as Dr. Carpenter could be found to teach 

 us in 1868 that a perfectly dry rotifer could be revived. J It is equally 

 improbable that you, sir, would have invited your subscribers to make 

 experiments and give you the results if celebrated writers had worked 

 out and disposed of the subject at least ten years before. § Further, 

 if he believed in the finally " settled " facts, how could Mr. Slack 

 himself, so recently as 1871, be found advocating opinions in direct 

 opposition to them ? || 



"The whole question" has never "turned upon the amount of 

 desiccation," as the rival theorists always distinctly stated their 

 opinions for or against " perfect desiccation," which can scarcely be a 

 comparative term ; and when in the ' Marvels ' Mr. Slack shows the 

 necessity for " thorough dryness " (his own italics), he surely does not 

 mean even a very slight partial dampness. 



The truth is that writers on the driest of all subjects just left it in 

 a state ripe for re-opening whenever new facts could be elicited, and 

 such facts (although most strangely ignored by Mr. Slack) I submit 

 are to be fcmnd in my small contribution to the Society's 

 1 Proceedings.' 



To those Fellows who have kindly testified their unsolicited 



* " No chemist would have expected to dry the rotifers by the process which 

 did not succeed - ' (in killing them?). — Vide Mr. Slack's letter, 

 f ' Studies in Animal Life.' 



j ' The Microscope and its Revelations,' 4th edition, pp. 477 and 480. 

 § " Desiccation of Rotifers," ' M. M. J.,' May, 1869, p. 315. 

 || ' Marvels of Pond Life,' 2nd edition, p. 132. 



