437 



ON THE PRESERVATION OF MARINE 

 ANIMALS. 



H. C. SORBY. LL.D., F.R.S., etc., 

 Sheffield. 



Though for some years I have been appointed Chairman of the 

 Section of Marine Biology of the Yorkshire NaturaHsts' Union, 

 I have so far done nothing to advance its objects. This is not 

 because I have taken no interest in the subject, but because at 

 the time of our meetings I am residing on my yacht occupied 

 with marine studies in a distant part of the country. The 

 following is a short account of the sort of work I have been 

 carrying on for many years, and possibly some of our readers 

 may find portions of it a suitable study for themselves. 



About twenty years ago my attention was directed mainly to 

 the determination of the number per gallon of the various free 

 swimming animals and plants in both fresh and salt water. At 

 that time so little notice was taken of this kind of work that 

 I did not continue it for more than a few years; but, since then, 

 very much attention has been directed to such organisms under 

 the name of plankton ; though often more with relation to the 

 nature of the material than to the number of the organisms per 

 gallon. I have lately been engaged in collecting together and 

 discussing all my observations, hoping soon to publish full 

 particulars, since the results seem to be of much interest. 



Nearly fifteen years ago it occurred to me that it would be 

 possible to dry marine animals on glass and mount them in 

 Canada balsam to be used as lantern slides. I have thus 

 prepared a good many hundred specimens, belonging to nearly 

 all those groups of marine organisms which are not too large or 

 too small for the purpose. In some cases great difficulties had 

 to be overcome before satisfactory results could be obtained, 

 but by perseverance nearly all have been overcome, so that in 

 many cases not only the form and colour but even much of 

 the anatomical structure can be seen when they are used in 

 a lantern. In most cases the natural colour has not sensibly 

 faded in a dozen years when so kept as not to be exposed to 

 strong daylight. There are, however, cases in which the struc- 

 ture is better seen by destroying some generally diffused pig- 

 ment by the action of strong sunlight, and leaving another 

 which shows important detail. I cannot now enter into par- 



190^ November i. 



