551 



Note on a Method of taking Internal Casts of 



foraminifera. 



By H. J. Quilter. 



{Read May loth, 1903.) 



It may be of interest to some to know that very fair internal 

 casts of some, at least, of the Foraminifera can be taken in 

 paraffin wax. 



The idea of taking these casts was first suggested in a con- 

 versation which I had with Mr. Earland about a year ago, and 

 soon after, the first casts were made by dropping the shells into 

 melted paraffin wax, in which they were left for a short time, 

 then picking them out and rolling them on a slip of glass 

 just warm enough to melt the wax. This method was on the 

 whole unsatisfactory, as although perfect casts were obtained, they 

 were too fragile to bear much handling. This was due to the fact 

 that a large part of the wax inside the shell ran out again, 

 leaving the casts hollow. Then casts in bees-wax, in resin, in 

 Canada balsam, and in various compounds were tried, but none 

 of these gave such good results, or were as easy to manipulate as 

 paraffin wax. It was realised that a solid cast was necessary in 

 order to obtain the necessary strength and tenacity, and, after 

 prolonged experiment, I have succeeded in obtaining perfect 

 specimens by the following method. 



The shells, having been cleaned by boiling in caustic potash, 

 in order to remove all trace of sarcode from the tubuli, are first 

 soaked in benzole. This extracts most of the air, and prepares 

 the surface of the shell for the wax. They are then transferred 

 to melted paraffin wax (the higher the melting point the better), 

 and the wax is then heated and cooled several times, the object 

 being to expel air. After all air-bubbles have disappeared from 

 the shells, a Sin. x lin. glass slip is cleaned, and a little of the 

 wax in which the shells are soaking is put in its centre, and the 



