ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 385 



alcohol, and then the paper is removed carefully. If the right con- 

 ditions of moisture are present, the sections should now adhere to the 

 glass. If the block is already stained, the sections may now be cleared 

 with creosote, treated with xylol and mounted in balsam. Otherwise it 

 it is necessary to apply descending alcohols, stain, dehydrate, and mount 

 as usual. 



Rubaschkin's method consists essentially in removing the section 

 straight from the razor to a slide prepared with albumin glycerin. He 

 lays stress on the importance of arranging the section smoothly upon 

 the slide. The section is then cleared with a mixture of equal parts of 

 clove oil and aniline oil. 



The author has made a comparison of the two methods, and considers 

 the former to be more suitable when a large number of sections are to 

 be dealt with, the latter more suitable for a small number. When it is 

 necessary to stain the sections, he considers it likely that Favaro's modi- 

 fication of the Italian method would be satisfactory, but disclaims per- 

 sonal experience of it. In this process the sections are stained while 

 still on the unglazed paper and before fixation to the slide. 



Mounting Spider Dissections as Microscopical Objects.* — The 

 following method of sealing a mixture of equal parts of glycerin and 

 spirit, a medium of great value in the mounting of the palpi of spiders, 

 can be strongly recommended. Slides so prepared have stood the test of 

 hard wear for more than two years, and show no signs of deterioration. 



A tin cell is smoothed on both sides with fine emery cloth. It is ce- 

 mented to a perfectly clean slip with good gold size and set aside until 

 hard. The edge of the cell is painted with Miller's caoutchouc cement, 

 which is allowed to become " tacky " but not dry. The medium and object 

 are introduced, a cover placed in position, and a clip added. The whole 

 is now well washed to remove all glycerin, and the clip is then removed 

 under water. A little water will enter the cell, but this is no disadvan- 

 tage. The slide is then wiped dry as far as possible, the remaining 

 moisture allowed to evaporate, and a ring of gold-size painted on. In 

 a day or so a ring of club-black is added, which completes the process. 



Since this method was published, F. P. Smith says he has had several 

 complaints as to the difficulty of obtaining Miller's cement, and that 

 " C. R. Percival, the well-known mounter, to whom I communicated this 

 method some years ago, tells me that he has used as a substitute an india- 

 rubber cement supplied by Griibler, with complete success." 



(6) Miscellaneous. 



Filtration of Immune Sera.f — E. H. Ruediger finds that serum, 

 after being centrifuged for 30 minutes at a speed of 3000 revolutions per 

 minute, will pass without clogging through a Berkefeld filter, N or W. 

 If, however, the serum be not quite cleared by the centrif ugalising, it is 

 well to pass it first through the coarser Berkefeld V filter. The centri- 

 fuge removes blood corpuscles, precipitates, and other extraneous matter. 



By experiments with anti-tetanic and typhoid agglutinating sera, the 

 author found that no appreciable loss in potency was caused by filtering. 



* Journ. Quekett Micr. Club. x. (1909) pp. 473-6. 

 t Philippine Journ. Sci. Manila, iv. (1909) pp. 333-40. 



June 15th, 1910 2 d 



