208 NOTES AND MEMORANDA. 



matiiYity possessing filiform and pointed pseudopodia. It is 

 the mature form which we must assume as presenting the 

 essentially characteristic conditions ; but I, at the same time^ 

 wholly agree with Hertwig in regarding the kind of pseudo- 

 podia possessed by the mature sarcodine as a constant and 

 eminently characteristic feature. — Wm. Archer. 



Calberla's New Embedding Mixture. — The embedding mix- 

 ture^ to which the following account has reference, gives, so 

 far as my experience goes, most useful results. The objects 

 which I wished to embed w^ere the more delicate portions of the 

 nephridia, or segmental organs of the common Earth worm, 

 which are so extremely fragile that I had found it impossible 

 to obtain adequate sections by the ordinary wax and paraffin 

 methods ; indeed, I had almost given up the attempt in 

 despair, when the paper which is the subject of the present 

 notice was put into my hands by Professor Lankester. The 

 method of preparation, although somewhat troublesome, is, I 

 think, capable of simplification ; the mode in which this 

 might be done, and the difficulties to be overcome, as well 

 as the special merits of the material will be pointed out 

 below. 



The embedding mixture was made by Dr. E. Calberla, of 

 Freiburg, on the principle of a somewhat similar substance 

 proposed by Drs. Bunge and Rosenberg. It is meant for 

 small and delicate objects, such as eggs and embryos, which 

 are embedded as a whole, whilst the sections can be mounted 

 and examined without that picking away or dissolving of 

 the embedding material, which is such a fertile source of 

 annoyance and discomfort in the ordinary methods of paraffin 

 embedding. An account of Dr. Calberla's mode of prepara- 

 tion was published in the * Morphologisches Jahrbuch,' vol. ii, 

 pt. 3, p. 445, 1876, The following is an abridged account : — 

 Make, in the first place, a 10% solution of calcined sodium 

 carbonate, the soda3 carbonas exsiccata of the British Phar- 

 macopoeia : then remove the yolks from the whites of some 

 hens' eggs ; the number of eggs used will, of course, depend 

 upon the amount of material required ; I find that for ordi- 

 nary purposes three are amply sufficient ; pick aAvay the 

 chalazae, and cut up the whites with a pair of scissors ; to 

 every fifteen parts of the albumen thus prepared add one part 

 of the sodium carbonate solution, and shake the wliole mix- 

 ture vigorously : then add the yolks of the eggs which have 

 been used, and again shake energetically for a minute or 

 two : now, pour the mixture into a deep vessel, allow it to 

 stand for a short time, and then skim off all the bubbles with 



