ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 701 



examination, while the curara method by itself requires at least a 

 quarter of an hour. 



The second procedure is a very simple method for influencing the 

 rapidity of the blood current in the larval tail. It depends on 

 Dr. Mayer's observations that by the imposition of the cover-glass 

 the blood current ceases in the covered parts of the larva, even 

 though the cover-glass be supported at the edges by glass splinters, 

 but that it is again restored as soon as a drop of water is run under 

 the cover-glass. Dr. Mayer traces back these appearances to the 

 pressure which exists in consequence of the capillary adhesion 

 between the cover-glass and the highest point of the object. The 

 addition of water whereby the cover-glass is removed from the object, 

 now brings it to pass that the capillary-adhesion pressure is either 

 diminished or altogether removed according to the size of the drop 

 added. Accordingly in the size of the drop of water exists a means 

 of keeping the blood current at its normal rapidity, or of diminishing 

 it in any desired degree to complete arrest. 



Preparing the Radula of Cephalophorous Mollusca.* — Dr. E. 

 Rossler places the living animals for half an hour in a moderately 

 hot concentrated sublimate solution ; then having got ready the 

 pharynx, he treats it for another half hour with sublimate, washing 

 thoroughly with water and staining with picro- or borax carmine, or 

 with hsematoxylin. 



According to the author, paraffin penetrates between the toothlets 

 of the radula with great difficulty, and most sections are con- 

 sequently torn in cutting. The best results were obtained by trans- 

 ferring the object from absolute alcohol to yellow benzol, slowly 

 adding warmed paraffin, and finally transferring to pure paraffin. 

 The paraffin is afterwards dissolved out in benzol. Turpentine oil 

 should be avoided, as it makes the radula brittle. 



Thin Sections of Entomostraca, &c.f — Dr. G. W. M. Giles de- 

 scribes a method of obtaining thin sections of Entomostraca and other 

 minute crustaceans, which he believes is somewhat novel. On account 

 of their small size and the hardness of their chitinous coats, they do 

 not lend themselves well to the paraffin method, as the knife is apt 

 either to ride over them or to compress them, and drive out the 

 paraffin filling up their interstices. Moreover, on account of the 

 bulk of the apparatus and the difficulty of maintaining a constant 

 temperature by means of spirit-lamps, it is extremely difficult in 

 practice to carry it out on shipboard. The method described is, 

 however, a somewhat rough and uncertain one, and it is only occa- 

 sionally that results at all comparable to those of the paraffin method 

 are obtained. It is, moreover, applicable only to very minute 

 organisms. 



The course of procedure is as follows : — The animal is taken 

 from absolute alcohol and immersed in oil of cloves, where it is left 

 until it is completely clarified. It is then placed in a watch-glass 



* Zeitschr. f. Wiss. Zool., xli. (1885) pp. 447-82 (2 pis. and 1 fig.). See this 

 Journal, v. (1885) p. 431. t Sci.-Uossip., 1886, p. 122. 



