4 BealEj on a Portable Field or Clinical Microscope. 



In examining objects by reflected ligbt, sufficient illumina- 

 tion is obtained from an ordinary wax candle placed at a 

 short distance from the aperture, just above the object. But 

 the most beautiful effects are obtained by using the Lieber- 

 kuhn with direct light. 



The slide, as has been stated, is kept in contact with the 

 lower part of the instrument, which I have called the stage, 

 by a spring which is therefore made to press on the back of 

 the slide. On the other side of the stage the little screw and 

 clamp are placed so that the specimen may be fixed in any 

 position that may be desired. 



In using this microscope the slide with the object to be 

 examined is placed upon the stage, the thin glass being up- 

 wards towards the object-glass, while the spring is made to 

 press upon the under surface of the slide. The little screw 

 is removed. The slide may now be moved in every position_, 

 and any particxilar object to be examined can readily be 

 placed exactly under the object-glass. Tube a is withdrawn 

 about two thirds of its length. The tube c being firmly held 

 with the left-hand, b is grasped with the right, and with 

 a screwing motion the object-glass is brought to its proper 

 focus. The specimen having been fixed Avith the little clamp, 

 and the bolt arranged at the right height, the instrument 

 may be passed round a class. This microscope seems to be 

 well suited to field-work and botanical purposes. It is not 

 heavy, and, including the powers and an animalcule cage, 

 will easily pack into a tube or case six and a half inches 

 long and two inches in diameter. I constantly use it in 

 clinical teaching. Urinary deposits, specimens of sputum, 

 &c., may be examined by the patient^s bedside, and their 

 characters demonstrated to the class. Lately, I have fitted 

 the instrument to a little stand, on which a light has been 

 placed in a suitable position, and the whole has been passed 

 round in class, while the characters of the object shown were 

 being described. When the arrangements are perfected, I 

 believe this form of instrument will be found very valuable 

 for demonstrating the microscopical characters of objects to 

 a large number of persons assembled in classes. 



The instrument can be seen at Mr. INIatthews^, Portugal 

 Street, Lincoln^s Inn, 



