BOTANICAL GAZETTE. 194 



piece (A or B); 8-10 objective, 24°; 1-5 objective, 75°; and Walnut 

 Case, which, with Lock and Handle, is sold at $38. There are other 

 instruments at as low, or nearly as low prices, which are also capable 

 of doing as good original work. Now then I will make the direct 

 statement. U you contemplate jiurchasing a microscope, do not delay 

 until you can purchase the most complicated. You will be astonished 

 when you come to discover the real capacity of such as I have indi- 

 cated. 



The instruments most in use in the laboratory of Prof, de Bary are 

 those of Hartnach, small, compact, without sub-stage or without joint 

 to turn the tube back. The optical parts are of course good and 

 give a magnifying power of about six hundred diameters. 



Means OF MAKING SECTIONS. Razors alone are used. These may 

 or may not be flat on one side. The knife which we have here speci- 

 ally made for the purpose is not requisite, and therefore an unneces- 

 sary cost. Neith(-r do we find in use the expensive section holders, 

 which figure so conspicuously on the tables of our amateurs. As a 

 means of holding a small soft specimen, pith taken from any plant 

 which furnishes it more than half an inch in diameter is sufficient, and 

 is much belter than cork, which is often used in the English laborato- 

 ries, as the latter often contains grit enough to dull the razors. The 

 cylinder of pith is simply cut down the middle and in pieces sufficient- 

 ly long to be comfortably held by the thumb and finger, and the ob- 

 ject is placed between. Or, for very small, precious objects, a few 

 drops of stearine are allowed to fall from a candle on a glass slide, 

 then, when cool, the object placed upon it, and a few drops more 

 placed on top and the whole allowed to harden, then by slightly warm- 

 ing the slide, the mass may be removed and held as in the case of the 

 pith. The adhering stearine has the advantage of being readily re- 

 moved by alcohol from the section. As for the object, it is safe to as- 

 sert that the custom is to make it as thin as possible, and always much 

 thinner than we are accustomed to make it here. As a rule, the 

 mounting medium is glycerine, and no attempt is made at staining or 

 double staining. To make a permanent mounting of a desirable 

 preparation, the Asphalt cement of Neumann & Son, Berlin, 51 Tau- 

 ben Strasse, is used, and to prevent this from being Iwosened by the 

 contraction of the cement as it hardens, a very fine thread of glass is 

 placed under one side of the cover glass. After considerable trial I 

 am very well satisfied a much better mode is to either make a thin 

 ring of a strong solution of gum shellac in alcohol and allow it to 

 harden an d then mount as before, or to make the first coat, at least, 

 of this and then place a subsequent coat of Asphaltum 

 over this when it has hardened. I am bound to say that I have used 

 no American cement that 1 did not like as well as that of Neumann, 

 though, from the fact of its being in use in all the laboratories of Eu- 

 rope, it must have decided merit. It hardens very quickly. For du- 

 rability, however, one cannot well forget the decided statement of Dr. 

 Carpenter, that, after thirty years experience and trial of gold size, he 

 had come to prefer it. 



For the softer, thinner tissues there can be no doubt but the Euro- 



