172 



SCIENCE-GOSSIP. 



concerned, the fissure yielded but three or four 

 flint flakes, and none of these were really good 

 examples or convincing specimens of man's handi- 

 work, but outside in the valley we have a mag- 

 nificent series, some of which in form, type, work 

 and condition are indistinguishable from the older 

 specimens of the Somme and Thames. (Vide 

 " Natural Science," vol. iv., No. 26, April, 1894.) 

 From the facts here indicated, and many others, 

 we are led to conclude that these arctic fauna and 

 implements were contemporary with what has 

 usually been considered man's advent in Britain. 

 This interesting discovery, however, helps to 

 associate valley-man more closely with the glacial 

 period, as did the finding of Betula nana at the 

 Admiralty section, so closely, indeed, that had we no 



other evidence we should be justified in regarding 

 him as glacial in the ordinary acceptation of that 

 ambiguous term. But in this neighbourhood we 

 have other sets of positions with other types of 

 implements, altogether ante-dating the present 

 physiography — the hillmen of Professor Prestwich. 

 There are then vestiges of prodigious erosive action 

 and concomitant phenomena separating us by an 

 extremely long period from yet another set of men 

 who lived upon the wealden plateau or mountain 

 sides. Day by day the discoverers of relics of our 

 pre-glacial and eolithic progenitors are thundering 

 from various parts of the Kingdom, which must, 

 ere long, wake the last slumberer from his post- 

 glacial-man nightmare. 



Seale House, Sever.oaks, Kent. 



PRACTICAL HINTS OX MARINE ZOOLOGY 



By Professor A. C. Haddon. 



f Continued from page 153 ) 



IV.— PRESERVING MARINE ANIMALS. 



COME specimens can be dried, such as the 

 ^ skeletons of sponges, hydrozoa, polyzoa, many 

 worm-tubes, the shells of brachiopods and mollusca 

 and the majority of the Crustacea. These should 

 be washed in fresh water to get rid of the salt. 



A collection of dried sponges and zoophytes is by 

 itself of little value, the only satisfactory method 

 of preserving them being to keep them in alcohol 

 in jars and tubes. Pieces of the hydrozoa and 

 polyzoa should be mounted as microscopic objects 

 but in all cases well-preserved specimens should be 

 selected so as to show the nature and structure of 

 the animal itself. 



The alcohol (methylated spirit) used for con- 

 serving specimens should never get below seventy 

 per cent, spirit (the thirty per cent, being water). 

 Too many specimens should not be crowded into a 

 bottle ; delicate forms require to be preserved 

 separately from others, and in all cases it is well 

 not to be stingy with the alcohol. Many animals 

 can be put straightway into alcohol ; later the spirit 

 will require to be changed once if not twice. 



It is customary to first kill certain animals 

 before placing them in spirit ; the fluids or 

 reagents employed for this purpose preserve the 

 tissues so that they can be submitted to delicate 

 microscopic study. This is in itself quite an art, 

 as different reagents have to be employed 

 according to the special work which is required 

 to be done. Information of this kind is best 

 imparted in properly equipped laboratories. The 

 two best books are "The Microtomists' Vade- 

 Mecum," by A. Bolles Lee, 1893, and '• Methods 



of Research in Microscopical Anatomy and 

 Embryology," by C. O. Whitman, Boston. 



Fortunately, when plentifully and carefully used_ 

 alcohol will answer most purposes. I have found 

 that chromic acid is very useful when one requires, 

 to preserve the form of such animals as worms, 

 nudibranchs and other soft-bodied creatures. Put 

 the living animal in a quarter per cent, solution for 

 from half-a-day to two days, then rinse it in water 

 or in weak spirit, put it in fifty per cent, for 

 half-a-day and keep in seventy-five per cent. ; a 

 sediment may appear, but the clear spirit can be 

 poured off and used again. With care, foul spirit 

 can be utilised for some of the preparatory stages. 

 It will be found convenient to take a stock solution 

 of chromic acid with you of considerable strength, 

 and when at the seaside fill some spare bottles 

 with the diluted fluid. 



A mixture known as Pereny's Fluid is extremely 

 serviceable, it consists of seven parts of twenty per 

 cent, nitric acid, seven parts nineteen per cent, 

 chromic acid and ten parts ninety per cent, of 

 spirit (ordinary methylated). The animals may 

 be kept in this almost any length of time, say from 

 twelve hours, then wash and treat with grades of 

 alcohol. 



One of the best all-round reagents is corrosive 

 sublimate ; of this a saturated or very strong solution 

 is employed, which can be used repeatedly. The 

 specimen must be washed and preserved as after 

 using chromic acid. Care must be taken not to 

 let any steel come in contact with the corrosive 

 sublimate. 



