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illusti-ation— practical as fai- as possible— of cuttings for micro- 

 scopes, and of all the instruments which they had at command, as 

 •well as the mode in which they were employed. 



The first and most valuable cutting apparatus which he should 

 bring before them was the instrument invented by Richard Beck, 

 which possessed a very fine screw, having 43 turns to the inch, so 

 that one revolution would lift it a 43rd part of an inch, and a fraction 

 of a turn would obviously diminish the distance accordingly. The 

 large head of the screw was so devised that it was divided into 

 25 parts, so that one was enabled to make a cutting by this 

 machine of a thousandth part of an inch theoretically, and 500 

 parts of an inch practically. The plate, too, was remarkably true. 



The instrument was invented for the pui-pose of cutting 

 wood and sections of vegetable substances of a certain degree of 

 hardness with a chisel. If, however, the subject were soft, a razor 

 must be used, and for specimens of this nature he could not say 

 Beck's invention was so valuable as it was for hai'd substances. 

 He had fixed upon the surface of the machine a piece of plate glass, 

 — the truest that he could procure, — to avoid friction and to allow 

 the instrument used for cutting to pass over it more readily, an 

 idea which would be found to be as correct in practice as it 

 was in theory. There was another machine sold by Baker, of 

 Holborn. The operation of the sci-ew was the same, but it was not 

 finished in the same neat and exact manner, so that it was 

 impossible to get the same refinement in the sections produced by 

 it. Mr. Haselwood, he believed, had also brought one of the most 

 recent inventions, which had the advantage of a refrigerating 

 apparatus. 



Ml'. Haselwood explained a section cutting machine known 

 as Professor Rutherford's. This was provided with a refrigerator, 

 which, being filled with ice and salt, solidified the wax or other 

 substance in which the object cut was " mounted." The screw was 

 a very fine one and was furnished with a spring, which would fix it 

 at any part of its turnings. There was a difficulty of obtaining a 

 proper section of very soft substances, such as animal tissue, but 

 he believed the Germans were able to cut a section clean through a 

 man's brain, a very difficult operation. 



