128 THE PRESERVATION OF MARINE ANIMALS 



Strength of 70 per cent, is to be always used for the final preserva- 

 tion of specimens in stoppered bottles or museum jars. When 

 specimens are placed first in weak alcohol, 30 per cent, is used, and 

 the intermediate strength to be employed is 50 per cent. Ordinary 

 methylated spirit is about 90 per cent, in strength, or more ; that is, 

 it contains 10 parts of water to 90 parts of alcohol, and it must be 

 diluted with the proper quantity of water to obtain the other 

 strengths. It is sufficiently accurate to add 20 parts of water to 100 

 parts spirit for 70 per cent, alcohol, equal parts for 50 per cent., and 

 30 parts spirit to 100 parts water for 30 per cent. The most conve- 

 nient measure to use is cubic centimetres, the measurement being 

 made in tall glass jars graduated in those units. 



In using corrosive sublimate and most other reagents it is 

 advisable to use wooden forceps and wooden rods or quills for 

 manipulation. The use of the fingers should be avoided as far as 

 possible ; if they are used the hands should be well washed with 

 fresh water immediately afterwards. In flooding with sublimate 

 or acetic acid, the small vessel containing the specimen in sea 

 water should be placed in an empty pie dish or porcelain photo- 

 graphic dish, and the specimen may be washed out of the small 

 vessel into the larger. An enema syringe is best for large injections; 

 for small animals pipettes are used, made from a piece of glass tube 

 drawn out at one end in a gas flame, and fitted at the other into an 

 imperforate india-rubber teat. Finally it may be repeated that 

 nothing but attention and care, together with practice, can ensure 

 success in preserving marine animals. 



The present paper only deals with preserving specimens entire 

 for museum purposes. For histological microscopic investigation 

 and special study of organs and tissues many other methods are 

 in use ; but, nevertheless, specimens properly preserved by the 

 methods mentioned above usuaHy have their tissues in a condition 

 which is to some extent suitable for dissection and microscopic 

 study. It may be mentioned here that small portions of Hydrozoa 

 and Bryozoa prepared as above directed make beautiful microscopic 

 preparations if stained with picro-carmine and mounted in Canada 

 balsam in the usual way. The piece' must be left in picro-carmine for 

 half an hour, then washed in water, transferred to successively stronger 

 mixtures of alcohol, and finally to absolute alcohol. After all the water 

 is removed by the latter, the specimen is transferred to clove oil or 

 turpentine, placed on a slide, a drop of Canada balsam dissolved 



