5 o8 SCIENCE PROGRESS 



assumption that the vermilion used for producing red vulcanite 

 contained mercury and would therefore lead to mercurial poison- 

 ing. There is little doubt that the early form of vulcanite did 

 cause considerable irritation to the mucous membrane of the 

 palate, but modern knowledge has caused these difficulties to 

 disappear. 



Later on pink celluloid was introduced as an apparently ideal 

 substance for artificial plates owing to its mucous-membrane- 

 like colour ; the early enthusiasm of its introducers, however, 

 soon abated when it was found that its lasting properties were 

 only to be measured by months owing to a constant tendency to 

 change of shape as well as certain other great disadvantages 

 which rendered it useless as a substitute for vulcanite. 



The so-called " crown and bridge-work," which we have 

 shown existed as far back as the ancient Etruscans, was revived 

 by our American cousins in the " sixties," and up to recently 

 may be said to have carried all before it ; marvellous mechanical 

 ingenuity was displayed, and from the jewellery point of view, 

 and apparently from the functional point of view, complete 

 dental restoration was obtained. 



A physician attached to one of the great London hospitals, 

 however, about the year 1901, sounded a note of warning which 

 seems likely to be a death knell to the famous so-called " bridge- 

 work." The point he sought to impress upon the medical pro- 

 fession was the serious results that follow upon an unhealthy 

 condition of the mouth and teeth. 



Special attention was drawn to the foul condition of "gold 

 bridges " as they existed in many mouths, the worst feature 

 being that the greater the mechanical ingenuity displayed, the 

 more unhealthy were the mouths concerned. The uncleanable 

 interstices of the " bridge " were hot-beds for the growth of 

 micro-organisms, and nowadays an increasing number of 

 surgeons, physicians, and dentists regard these complicated 

 pieces of apparatus as mere microbial breeding-places, and as 

 such, the sooner removed the better. It is becoming a common- 

 place for physicians practising at spas and health-resorts to 

 order their removal before commencing a course of anti-rheumatic 

 or gout treatment, with the remarkable result that many of the 

 chronic sufferers straightway recover their former health. 



The introduction of cocaine as a local anaesthetic for opera- 

 tions on the eye in 1878 led to its use for a similar purpose in 



