130 UNPRESSED MOUNTING FOR MICROSCOPE. 



seem to open easiest at the picture of '^ the tongue of a blow-fly " ; 

 they almost all have a drawing of it. And all these many tongues 

 apparently conspire to utter the same mis-statement of fact ; for 

 how few of us have ever through the microscope seen anything 

 but a squashed and flattened object ; — a something as like the real 

 thing as that flattened collection of dirty feathers over which 

 several cart-wheels have passed is like the once gay rooster 

 crowing on his own dung-hill. 



Now, seeing these are serious objections to the too-common 

 method of mounting, and suspecting that most of this distortion 

 of Nature results from not knowing how else to preserve micro- 

 scopical objects, we would lay before our readers what we consider 

 a better, easier, and more natural method : — a plan in which, from 

 the beginning to the end, the true shape of the object is preserved. 



Let us try whether we cannot mount our " Tongue of Blow- 

 fly," for instance, so as to see its true shape ; to have it transparent 

 in every part ; to be able to view each hair, every ramification of 

 the internal organs, trachece, etc., just in the positions they 

 naturally occupy. 



And, firstly, it is not necessary to wait till our blow-fly has his 

 tongue protruded over some piece of sugar, and then deftly to cut 

 it off with a pair of scissors. Nor need we squeeze the head to 

 make the tongue protrude, nor pull it out with tweezers. All such 

 methods mean the expenditure of a lot of time, and the slaughter 

 of a number of blow-flies, with the production of a few more or 

 less damaged and fragmentary objects. In fact, we will not cut 

 off the tongue at all, but mount it in its natural position on the 

 head; for our blow-fly's neck is so slender that there is no 

 difficulty whatever in decapitating him. We will, therefore, do so. 

 Now, if we consult our books on microscopical mounting, we find 

 that we must first dry the head, and then soak it in turpentine ; 

 or, as some say, put it at once in turpentine and wait till it is 

 transparent. If mounting anything but horses had been in vogue 

 in Methuselah's days, such methods would have been then well worth 

 trying ; there was no need for hurry in those happy times. Those, 

 perhaps, were the days when they placed knobs of " Wallsend " in 

 carbonate of potash solution, and fished them out a century or so 

 later, just nice and soft for cutting " coal sections." Alas ! this is 

 now a lost art, in spite of the plain directions given in various 

 works on microscopical mounting ! But as we cannot wait the 

 months necessary for the blow-fly's head to become transparent (if 

 it ever would by this process), we will try a shorter plan ; for even 

 in microscopical mounting it is of some advantage to be reason- 

 able. And in order to make it transparent, we have first to get 

 rid of the mass of colouring matter and of all air ; since, of all 



