Thilenius. — On Formaline. 103 



the branches, leaves, &c., upon which they are found. The 

 easiest way is to put the whole branch or leaf into a glass 

 tube or jar, and a few drops of concentrated formaline on the 

 bottom of the glass, which will soon evaporate and preserve 

 the object. The glass has to be kept air-tight and well closed. 

 Cephalopoda are kept in a 2-per-cent. solution of formaline in 

 sea- water, which has to be changed several times. It is 

 advisable to inject a small quantity of the same solution into 

 the siphon of the animal. 



Shellfish, oysters, &c., are kept in the same way after open- 

 ing the shells, or removing one of them entirely. To avoid the 

 changing of the solution, the animal may as well be killed 

 by pouring boiling water over it. x\fter a few minutes the 

 coagulation of the albumen will be finished, and the specimen 

 may be mounted at once in the 2-per-cent. solution in 

 sea-water. In the same way slugs and snails may be 

 treated. To avoid the contraction of the body, before pouring 

 out the boiling water they should be anaesthetized or killed 

 in sea- water mixed with ether sulf. or cocaine. Generally 

 the Ttmicata may be preserved in the same way, if possible 

 using living animals. This is indispensable with Meduscs, 

 Salpa, PyrosovicB, &c. The best plan is to put them immedi- 

 ately from the net into a 10-per-cent. solution of formaline in 

 sea-water. They die in a few seconds, and coming home you 

 can select the specimens you require, which should be mounted 

 in a fresh 10-per-cent. solution. Siphonopliora have to be 

 killed in another way, to avoid the dismembering. The animal 

 is kept in as little sea-water as possible, in a much larger 

 (higher) jar. Then a large quantity of a solution of cupr. sulf. 

 (25 per cent.) is at once poured over it. After an hour or 

 less the specimen may be placed in a 2-per-cent. solution of 

 formaline in sea- water. Sea- worms, Aphroditce, &c., do not 

 keep in formaline. They are killed in a concentrated solution 

 of corrosive sublimate, and after about ten minutes washed out 

 in a weak solution of spirits of wine, and mounted in a spirit 

 of about 80-90 per cent. 



Specimens of any description which have been hardened 

 and preserved in spirits of wine may, without incon- 

 venience, be placed and kept in a 2-per-cent. solution of 

 formaline, the mixture of spirits and formaline being of no 

 consequence. Vertebrates, however, after a certain time will 

 not be fit for dissection and maceration, while Synayta, etc., 

 will have their calcareous formations destroyed. 



