The MicRoscorK. # 125 



tJiken from a potassium bichromate solution (weak) after four 

 clay's immersion showed the appearance very nicely. 



Prick, with a teasing needle, a small part of tissue from the 

 •gland. In size it should not exceed a millet seed, or three times 

 the mass of the head of a pin. Add some indifferent fluid such 

 as " artificial serum " or a weak salt solution (5 per cent.). Put 

 on large sized cover glass and examine with a ^ or ^ inch ob- 

 jective. Very gentle pressure on the cover glass will reveal the 

 flowing blood which, on stopping the pressure, actively rushes 

 back to a central opening (the intra-lobular vein), all the little 

 blood channels appearing like so many radii gathering into it. 

 Sometimes a repetition shows beautifully what a i)revious effort 

 failed to obtain. 



cwsp^nDcncE 



Editor The Microscope : — 



In the December number of The IMicroscope, " An Amateur " 

 writes : " On no account would I give an intelligent beginner a 

 stand with a short body tube." I wonder if he really intends 

 to advise an intelligent beginner to select an instrument with a 

 single long tube in preference to a short main tube with a draw ? 

 In the same paper he writes that on no account would he give a 

 beginner a stand Avith a single eye piece. He will find much 

 criticism unless he can give some good reason for his advice. 

 Many would prefer the following: First select a good stand 

 with low eye piece, and then the best objectives obtainable 

 with sufficient power to accomplish the work desired, bearing in 

 mind that increased power should always be secured by suitable 

 objectives in preference to deep eye piecing for the reason that 

 any defect in the objective will be magnified by the ocular. 



" Amateur's " exact meaning of " Buy one with what seems to 

 Si multiplicity and a complexity of movable parts " is not clear. 



