448 ON A CASE OF EXCISION OF THE KNEE-JOINT 



or nil, a bandage steeped in waterglass (a mixture of the silicates of soda and 

 potash) will be wound round the limb as it lies in the splint, so as to ensure 

 absolute immobility. 



Now, gentlemen, these various matters have been much more easily demon- 

 strated to you here than they could have been in the ward. I was much struck 

 with the difference between the theatre and the ward in this respect when 

 showing in the ward to some strangers, after our lecture this day fortnight, 

 the case of large granulating sore which I have brought before you here on 

 several occasions. Our class is not a large one, numbering only fifty, and 

 I suppose not half that number accompanied me to the ward. Yet in order to 

 show the ulcer, it was necessary that those gentlemen should arrange themselves 

 in two rows, so as to form an alley to admit the light from the window, and even 

 then they stood in one another's way, and only those who were very near the 

 bed could see what would have been shown without any difficulty to the whole 

 class at once in this place. In connexion with that case I may make some 

 further remarks regarding the mode of teaching which we employ. 



Let me remind you of the various important matters which that ulcer has 

 afforded the opportunity of demonstrating. First, you recollect how putrid the 

 sore was at the outset, and how we succeeded in purifying it once for all 

 by applying to the epidermis soaked with putrid discharge a strong watery 

 solution (i to 20) of carbolic acid, which has a special power of penetrating the 

 epidermis, and to the granulations a solution of chloride of zinc (40 grains to 

 an ounce), which experience has shown to have an energetic antiseptic effect 

 upon foul granulations. That we did really purify the sore by this application 

 was proved to you by the fact that, being afterwards dressed with lint con- 

 taining boracic acid, which is the mildest of our antiseptics, with a piece of 

 prepared oiled silk interposed between it and the granulations, to protect them 

 from the antiseptic, mild as it was, and to ensure constant moisture of the 

 surface, yet when dressed after an interval of a week, the oiled silk, instead of 

 being putrid as it would have been in twenty-four hours under a piece of ordinary 

 lint, had no odour except that of oiled silk itself. The pus had remained free 

 from putrefaction for that long period, though not directly acted on by an 

 antiseptic at all. 



You have also had demonstrated to you on that sore some very important 

 truths regarding the properties of granulations. You saw me clip away with 

 scissors a portion of the surface without occasioning the slightest pain to the 

 patient, proving that the granulations constituted a protective layer destitute 

 of sensibility. 



Again, we made an accurate pattern of the ulcer in gutta-percha tissue. 



