1884.] 



MICROSCOPICAL JOURNAL. 



143 



business to attend to, or who does 

 not care to devote all his spare time 

 to the perfection of a single mount. 



Thinking that a simple method of 

 grinding used by myself for some 

 years past would be of advantage to 

 your readers, I send the following. 



I have elsewhere noticed a short ar- 

 ticle by Mr. Jacobs upon making sec- 

 tions of teeth with pulp, in which he 

 describes very nearly the same method 

 of grinding. But as I have a little 

 more to say upon this subject, I take 

 the risk of repeating some things, as 

 the subject will surely bear recapitu- 

 lation. 



I use nothing but perfectly fresh 

 tissue, which I take to a dentist's of- 

 fice, where one generally finds a good 

 polishing lathe with a set of emery 

 wheels, and rapidly grind down one 

 side after another of a tooth or sawed 

 section of bone by holding the same 

 firmly between my fingers and thumbs 

 against the edge or circumference of 

 a coarse stone. In a few minutes I 

 am thus enabled to grind down a 

 rough section to about ^ of an inch 

 in thickness. I keep the section and 

 stone thoroughly wet in cold water, 

 to keep it moist and cool. As the 

 section becomes too thin to hold as 

 before, I wet the evenly sawed end of 

 about a one inch cube of soft pine 

 block, and place the tooth upon this, 

 where it is held sufficiently secure 

 upon a firm and even bed. I then 

 press the section against the side of a 

 finer stone, and after working it down 

 reasonably thin I change it to the finest 

 and best polished stone a dentist makes 

 use of. 



In polishing, instead of the block 

 I often make use of the palmar sur- 

 face of my index finger, and I now 

 prefer it. It is simply surprising to 

 see how easily and delicately one is 

 enabled to do this with a little prac- 

 tice. If a part of the ball of the fin- 

 ger happens to come in contact with 

 a finely polished and well-moistened 

 stone it will have but little if any ef- 

 fect upon the epidermis. I generally 

 make use of a lathe run by a water 



motor, but foot-power answers quite 

 as well. In this way I can have a 

 tooth ready to mount in thirty min- 

 utes after its removal from the jaw. 



The above method has the follow- 

 ing advantages over the old and more 

 common ones, viz., rapidity of prep- 

 aration, and thereby the specimen re- 

 tains all of its original tenacity. It 

 does not curl up or become brittle, 

 and tlius one is enabled to get a larger 

 and more perfect specimen. During 

 the reduction and polishing the speci- 

 men can readily be removed from 

 time to time, washed, and the pro- 

 cess of reduction obsei*ved. I have 

 made perfect longitudinal sections of 

 teeth in this way which were so thin 

 that they wovdd bend under their own 

 weight. This would be simply im- 

 possible in a tooth that had become 

 dry during the old process, as they 

 become too brittle to allow of such 

 extreme reduction. 



A tooth may be ground to its cen- 

 tre, and the pulp kept hard by im- 

 mersing it in alcohol from time to 

 time, as suggested by Mr. Jacobs, 

 but I have not found this necessary 

 when a reasonable amount of care is 

 used. The pulp may then be stained, 

 and a very pretty and instructive 

 mount it makes. I have a section of 

 cat's jaw, with tooth in situ. The 

 bone corpuscles in the lacunae of the 

 jaw-bone and the pulp of the tooth 

 have been stained with Thirsch's car- 

 mine borax stain. The rapidity of 

 reduction and preparation thus read- 

 ily admits of vStaining the protoplasm 

 of bone sections before retrogression 

 sets in, and thereby their value is 

 greatly enhanced. 



I make use of the usual methods 

 of dehydrating and staining, and I 

 generally clear in benzole or carbolic 

 acid and spirits of turpentine, one 

 part to five, and mount in balsam. 



[A well-made section of a tooth 

 within its socket is a very fine speci- 

 men for exhibition. We have one 

 made by Mr. J. L. Williams, which 

 was purchased some time ago because 

 of its excellence, and it has proved of 



