148 The Microscope. 



to cut their sections as thin as possible, and the boast is frequently 

 made, that a certain number of consecutive sections have been cut 

 from ^oVtt ^o 4V^ocr o^ 3,n inch in thickness. Sections having a thick- 

 ness of ^oVo" i^ich can be cut, providing the preliminary operations 

 are carefully carried out; but, although the writer has had the oppor- 

 tunity of inspecting the work of many experts, he has not yet seen 

 a section approaching a thinness of j-oVtt inch, notwithstanding the 

 claims made for a number of those examined. 



The origin of this fashion of cutting over-thin sections is 

 difficult to determine, for such sections are, in the great majority of 

 cases, quite useless for any purpose of study, and the time involved 

 in their preparation is as well as wasted. It is probably due to a 

 desire to exhibit one's skill without regard for utility ; something 

 like that which induces one to write 10,000 words on a postal card, 

 simply because some one else has succeeded in wi'iting 9,000. 

 Friedliinder, in his excellent little manual of microscopical tech- 

 nology, raises the following objections to sections of extreme thin- 

 ness. " 1. They are manipulated with difficulty, and considerable 

 time is often lost in spreading them upon the slide. 2. The various 

 elements contained in the meshes of thin sections are very apt to 

 fall out ; and, as these are generally of extreme importance, the 

 object of the examination may be defeated. * * 3. Structures 

 which are sparingly distributed throughout an organ, as, for 

 example, animal and vegetable parasites, are naturally more apt to 

 be discovered in thick sections. * * 4. In thick sections definite 

 stereometric conceptions of the structure of an object are frequently 

 obtained, inasmuch as several superimposed strata are scanned 

 directly, in situ et in contimco ; while with the extremely thin sections 

 plane images alone appear. * * " For sections of fresh organs he 

 recommends a thickness of from ^^^ to -o\-^j inch, for hardened 

 preparations from 3-5*0 ^ to about g V^ inch. 



The rule should be then, not to make the sections as thin as 

 possible, but rather to have them of a thickness that will include as 

 many layers as can be clearly studied. 



We hope that some readers will give this matter of thin 

 sections a little study; for of the large number of mounts kindly sent 

 us by our subscribers, the chief fault, when they have any faults, is 

 generally that they are too thin to see anything worth studying. 

 If the mounter will see that his sections are, so to speak, of the 

 proper thickness, rather than thinness, we are quite sure that he will 

 not be long in recognizing the results as far more satisfactory. 



