

CHEMICALS in 



is not good for animals with calcareous skeletons or 

 scales, turning slightly acid, especially in the tropics ; 

 the much more expensive German patent formalin is 

 no better. For the minute anatomy of tropical marine 

 animals the best all-round killing agent is undoubtedly 

 corrosive sublimate (mercuric chloride) in saturated 

 solution in sea water. Picric acid is also valuable, 

 but the naturalist is warned that it is dangerous to 

 carry, being explosive ; it is forbidden on mail steamers 

 by the Board of Trade regulations.* 



Various anaesthetizing agents are used in temperate 

 regions, with excellent results, but most of them are 

 quite useless in the tropics, the animals it is desired to 

 obtain expanded being frequently found to have rotted 

 before the anaesthetic has taken effect. Pure spirit, a 

 few drops at a time, placed on the surface of the water 

 with a small pipette, is the only really good agent, as 

 it keeps the water clean, while gradually anaesthetizing 

 the beasts in it. It is very good for Balanoglossids 

 and worms. Generally speaking, it is a rule in the 

 tropics to get animals as quickly as possible into one 

 of the two preserving fluids, in which they can be 

 brought home — i.e., 70 per cent, alcohol, or 2 to 4 per 

 cent, formic aldehyde. 



To advise as to the amount of jars, bottles, and 

 tubes to be taken to any tropical locality is quite 

 beyond the author's powers without his knowing the 

 precise circumstances of each expedition, and is also, 

 perhaps, beyond his province. Very much may be 

 done with cheap galvanized tanks with screw lids, of 

 1, 2, or 3 gallons, the individual animals being wrapped 

 and tied up in butter-cloth, each with its label stating 

 where collected, etc. The spirit may be carried in 



* The most recent regulations ordain that it shall only be 

 carried in solution (191 1). 



