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V . — A New Method of Infiltrating Osseous and Dental Tissues. 
By T. Charters White, m.r.o.s., f.r.m.s. 
( Read 18 th March , 1891.) 
It is well known to all who are in the habit of mounting osseous or 
dental tissues in Canada balsam, that great care must be observed in 
order to keep out this substance from any existing tubular or cavernous 
elements in these tissues, in order to obviate the inevitable obliteration 
which would arise in consequence. It therefore occurred to me that if 
such cavities could be filled by some substance insoluble in the balsam, 
such obliteration would be prevented, and the minutest features of the 
section rendered visible. Several methods presented themselves to my 
mind, but none seemed to have greater advantages than that I wish to 
introduce to your notice this evening. I do not pretend that this 
method will demonstrate anything fresh in a known structure, but 
should abnormal histological elements be present they will be made 
evident more readily, while the well-known obliteration will be entirely 
removed. The plan by which for many years I have mounted hard 
dental tissues answered very well, and it may be of help to recall it 
as it has proved so useful in the hands of others who have adopted it. 
It was to grind the dental or osseous sections between two plates of 
ground glass, with water and pumice powder, till sufficiently thin, 
finishing them off at last with old and worn-out ground glass and 
water alone. This, while it allowed the grinding down to proceed more 
slowly, at the same time polished the section ; this being saturated with 
water only required cleaning and its surfaces dried, when it might be 
mounted in fairly stiff balsam, hut without heat . In this manner the 
internal cavities remained impermeable to the balsam. Thinking 
over this method with a view to its improvement, the thought occurred 
to me that if some method of infiltration could be adopted, such as is 
frequently employed in preparing the soft tissues, an advantage could 
be gained ; and I set to work to carry this thought into execution after 
this manner. The section may be cut or ground moderately thin and 
soaked in ether for about 24 hours or more, it is immaterial ; it may 
then be transferred to a thin collodion stained with fuchsin, where it 
may remain for two or three days to allow the stained collodion to follow 
the ether into the minutest ramifications of the tissue. In this 
manner not only the lacunae of bone are infiltrated, but their radiating 
canaliculi also, and the dentinal tubuli, equally fine in dimensions, 
are frequently found filled to their ultimate terminations. The section 
may now be placed in methylated spirit which will harden the 
collodion, and it may remain in this till a suitable opportunity arises 
for grinding it down to its final thinness. The collodion being 
insoluble in water, no detrimental action can ensue from the grind- 
ing down, but especial care should be taken to finish off with old 
