ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 327 



placed from 3-5 minutes in this solution, then washed for a few seconds 

 in absolute alcohol, and then transferred to the iodide solution, which is — 

 1 part iodine, 2 parts iodide of potassium, and 300 parts water. They are 

 finally decolourized in absolute alcohol, cleared up in oil of cloves, and 

 mounted in Canada balsam. 



Artificial Distortions of the Nucleus.* — Dr. 0. Van Bambeke em- 

 ployed principally the intestinal canal and Malpighian vessels of Arthropoda 

 in his researches. The organs or their parts taken from the living animal 

 were teased or spread out. Organs of tubular form, like the intestinal 

 canal, were first of all split up and their contents evacuated. The blood 

 of the animals could be examined without the aid of reagents ; yet it was 

 more advantageous to add a fixative and a staining medium. The author 

 preferred acid methyl-green, under the influence of which reagent the nuclei 

 of the eyes and their alterations could be easily studied. For permanent 

 preparations, fixation with osmic acid, staining with methyl-green, and 

 mounting in dilute glycerin were employed. 



The manipulation to which the organs were exposed produced alterations 

 in a large number of nuclei, and this alteration occurred also in various 

 proportions, according to the species examined. 



Demonstration of the Fibrillse of Unstriated Muscular Fibres. f — 



For demonstrating the longitudinal fibrillation of unstriated muscular fibres 

 the following method has proved very satisfactory according to Prof. S. H. 

 Gage : Ten to fifteen cm. of perfectly fresh small intestine from a cat or 

 other animal is tied at one end, and into the other is injected the following 

 mixture : 95 per cent, alcohol 25 c.c, water 75 c.c, picric acid crystals 

 3/4 gram. When the intestine is moderately distended, the end in which 

 the injection is made is tied, and the piece of intestine placed in a glass dish 

 and covered with the mixture. After one or two days the muscular coats 

 may be torn ofi" in shreds. If one of the shreds is teased well with needles, 

 unstriated muscular fibres may be partly or wholly isolated. They may 

 be mounted in 75 per cent, glycerin. The picric acid stains the fibres yellow, 

 and with a homogeneous-immersion (1/12 or 1/18) the longitudinal 

 fibrillation shows with the greatest clearness. In some cases the ends of 

 the fibres will be frayed, and show the fibrillse something like a brush. 



Preparation of the Organs of the Nervous System.| — Prof. G. Golgi's 

 improved method is as follows : — 



1. Combined use of bichromate of potash and nitrate of silver. This 

 depends on the gradual removal of the bichromate from the hardened pieces 

 by means of a half to 1 per cent, solution of silver nitrate. The reaction 

 is completed in 20 to 30 hours. This method is somewhat uncertain. 



2. Successive use of bichromate of potash, osmic acid, and silver nitrate. 

 Hardening is effected in a mixture of a 2 per cent, solution of bichromate, 

 8 parts, and 1 per cent, solution of osmic acid, 1 part. The pieces, which 

 must be very small, are then immersed in the silver nitrate solution. 



3. Successive action of potassium bichromate and perchloride of mercury. 

 This method requires from one month to a year (according to the size of 

 the pieces) for its full development, but a whole brain may be stained 

 through at once. 



Preparation of Amphibian Embryos.§— Dr. C. Eabl recommends that 

 the embryos of Salamandra maculosa and atra and Triton teeniatus should 



* Arch, de Biol., vii. (1886) 3 pis. t The Microscope, vi. (1886) pp. 267-8. 



X Milano, 1886. Of. Zeitschr. f. Wiss. Mikr., iii. (1886) pp. 409-10. 

 § Morphol. Jahrb., xii. (1886) pp. 252-7 (2 pis. and 2 figs.). 



