107G SUMMARY OF CURRENT RESEARCHES RELATING; TO 



sulphuric acid, aud a few crystals of chlorato of potash. Stronger 

 solutious had no greater effect. 



Preparing Fucus vesiculosus.* — For tlio demonstration and fixa- 

 tion of tho cells of the filaments on which the spermatozoid cells 

 exist as end-colls, Dr. J. Behrens used osmic and picro-sulphuric acid, 

 also iodine water and bromido vapour, and for staining, Schneider's 

 acetic-carmine. For the observation of nuclear fission in tho 

 anthoridium cells, carmine staining is not especially favourable. The 

 processes in tho spores and pcrispores must bo studied in fixed 

 material ; picro-sulphuric acid, bromide vapour, iodine water, boiling 

 water, chrom-osmic-acetic acid serve as fixative media, and in rare 

 cases alcohol and 1 per cent, acetic acid. Bromide vapour and boiling 

 water are the most convenient agents as tbey do not necessitate any 

 washing out afterwards. After staining, the objects are placed in 

 dilute and finally in absolute alcohol. When perfectly dehydrated, 

 they arc cleared in clove or turpentine oil, and mounted in balsam or 

 dammar. 



In order to render visible what had happened in the spore after 

 the penetration of the spermatozoids (occurrences hitherto unobserved 

 and invisible in the living spore by reason of its opacity), the author 

 mixed fresh spores with spermatozoids in a hollow ground slide, and 

 after some moments the spores were killed, usually with iodine 

 solution, and then stained and cleared up. 



Separating Desmids, Diatoms, and other minute objects. j — Mr. 

 C. L. Wilbur uses for separating desmids and similar objects from 

 the foreign matter with which they are associated in nature, a set of 

 suction-tubes, five in number, increasing and decreasing in fineness 

 from No. 3, which is large enough to comfortably admit a Cosmarium 

 tetraophthalmiim. These are ranged on a small wooden rack placed on a 

 box of convenient size at the right of the Microscope and are fitted in, 

 as needed, to a small flexible white rubber tube ; this fits over one of 

 two glass tubes put tightly through the stopper of a 1-oz. wide-mouthed 

 bottle, and to the other tube is fitted a second one of rubber which is 

 held in the mouth while at work or fitted to a convenient mouth-piece. 

 The tubes are filled with water on beginning work to a height sufficient 

 to satisfy capillary attraction. Then, working e.g. under a 1 in. objective 

 and B eye-piece, the point is brought nearly to the surface of tbe pool 

 on the slides and moved to and fro horizontally till shadow is seen 

 in the field, thence quickly brought with the point close to the object. 

 After a little practice the proper point can be inserted and instantly 

 brought to the object without taking the eye from the field. It can 

 now be sucked in and transferred to little pools of 50 per cent, 

 glycerin on a collecting slide, parcelling off like forms, different sizes, 

 &c, or, by alternately expelling and drawing in the breath, the object 

 can be rolled over and over by the current from the tube, thus show- 

 ing all sides. 



The author ordinarily takes samples with a small pipette, places 



* Ber. Deutsch. Bot. Gesell., iv. (1886) pp. 92-103. 

 t The Microscope, vi. (188G) pp. 109-71. 



