NOTES AND MEMORANDA. 209 



strips of paper, picking out at the same time, with a pair of 

 forceps, any membranous fragments. The material is then 

 ready for use as an embedding substance. When first using 

 the material a matrix or core has to be made ; for preparing 

 this Dr. Calberla uses the method to be presently described, 

 but inasmuch as this involves a great waste of time, I simply 

 pour some of the fluid material prepared as above into a test 

 tube, which is then corked up and put for five minutes or so 

 into a saucepan of boiling water ; on then removing the test 

 tube, the substance is found to have set quite firm ; the tube 

 is then broken, and a cylinder of embedding material is 

 obtained, which for all practical purposes is identical with 

 the substance hardened by the more elaborate method. A 

 groove is made in a bit of the cylinder thus obtained, about 

 an inch long, and the object to be embedded is placed in the 

 groove ; before doing this, however, the object is put into 

 water to free it from any trace of its preservative fluid, 

 where it is allowed to remain for from three to ten minutes : 

 then, if it is very delicate, it is put into some ordinary white 

 of egg, or into the fluid material itself, for a period varying 

 from five to twenty minutes, according to the thickness of 

 the object ; if it is liable to curl up the object is placed be- 

 tween two thin shavings taken from the previously hardened 

 material, and is then laid in the groove cut in the cylinder. 

 After placing the object in the groove which has been 

 cut to receive it, the cylinder is put into a small paper box, 

 such as is used in embedding with paraffin, and some of the 

 liquid material is poured over it till a layer is formed above 

 cylinder : the paper box is then suspended by a piece of the 

 thread in a vessel containing strong alcohol in such a way 

 that the paper box is immersed to at least half its height 

 in the alcohol, the vessel itself being placed in a water bath 

 whose temperature is so regulated that the alcohol does not 

 quite boil ; a funnel is inverted over the vessel, and thus the 

 paper box containing the object and embedding mixture is 

 exposed to the full vapour of the alcohol ; after remaining 

 in this position for 30-45 minutes the material will be found 

 to have attained a fairly marked consistency. It must now 

 be removed, the paper cut away, and the preparation put 

 into strong cold alcohol, which is changed after 24 hours. 

 It is not necessary to use a paper box if the block of hardened 

 albumen is carefully excavated so as to receive the object 

 which is to be cut and a sufiicient quantity of the liquid 

 albumen. It is necessary to expose the whole to the action 

 of hot spirit vapour in order to produce such a pellicle on the 

 surface of the liquid albumen as will allow of the whole mass 



