152 THE AMERICAN MONTHLY [August, 



MICROSCOPICAL METHODS. 



Investigating nerve tissues.* — In studies upon the histology of nerve 

 tissues Mr. F. Nanseu used both fresh macerated tissues for teasing and hard- 

 ened slices for sections. .Some fresh tissues were teased in the blood of the 

 animal as a medium and examined. Others were macerated in Hatter's 

 fluid, made of 5 parts acetic acid, 5 parts glycerine, and 20 parts distilled 

 water ; immersed 1-24 hours ; teased in 50 per cent, glycerine stained picro- 

 carmine. For sections he used Flemming's mixture, made thus: — 1% 

 chromic acid, i^ parts; 2% osmic acid, 4 parts; acetic acid, i part. Small 

 pieces of tissue must be treated in a large quantity of the fluid for 12-24 

 hours or longer. After washing they should be included (not imbedded) in 

 parafflne and cut under alcohol or water. A slight departure from Golge's v 

 method was used, as follows, upon Myxine glutitiosa : — The nerve cords 

 divided into pieces one or two centimetres long were laid in potassium 

 bichromate (2%) for an hour, then the solution changed and made a little 

 stronger and left 24 hours ; from this to solution of 4 parts 3/^ potassium bi- 

 chromate and I part i "n osmic, and left 3 days ; from this to wash of 

 .5x0 silver nitrate, and then in \% solution one day. wSections need not be 

 vei'y thin ; if the staining is good the ganglion cells will be seen with all their 

 processes, and ' nerve-tubes ' with their ramifications will appear quite dark 

 or black on a transparent field. Specimens should be mounted in balsam, 

 uncovered, the cover preventing the evaporation of the balsam solvent. 

 Mounts must, when not in use, be kept in a dark place. 



o 



New staining fluid. t — Mr. J. W. Roosevelt recommends an iron stain, 

 consisting of 20 drops of a saturated solution of iron sulphate, 30 grammes 

 water, and 15-20 drops pyro-gallic acid. The preparation assumes a brown- 

 ish-grey color. It is specially suitable for photo-micrographic purposes, be- 

 cause, when united with albuminous tissues, it undergoes no further change. 



Bismarck brown may be used for staining sections on slide, after being 

 held b}' collodion varnish, if the solution be made as follows: — Saturate i 

 part of absolute alcohol with Bismarck brown and add 2 paints of distilled 

 water. 



EDITORIAL. 



The scope of this Journal. —While attempting no considerable de- 

 parture from the course formerly pursued in this JonrnaP s literary manage- 

 ment, we, perhaps, have tried to make it less and less exclusively a strictly 

 technical magazine by admitting to its pages a considerable amount of matter 

 of popular interest in biology. Being thoroughly of the opinion that there 

 is a grow'ing interest in our colleges and lower schools, and also among the 

 business people of this country, in the young science of biologv, it has been 

 in part our purpose to present a record of some of the new things from the 

 world of biological science. In doing this we recognize two sources of ma- 

 terial for our pages ; first, the contributions of those who are meeting bio- 

 logical problems with their own microscope, and those who assist us bv 

 furnishing reports of progress from the great active field of study. Qiiestions 

 from subscribers show us from time to time how large an element the begin- 

 ners are among the readers. We well recall our own helplessness when at 

 the age of fourteen years we received at Christmas time a good microscope, 



*Journ. Roy. Micr. Soc, 1888, p. 312. 

 t Journ. Roy. Micr. Soc, 1S88, p. 157. 



