No. 10.-Amputation of left leg, upper third; doing well. No. ll.-Compound fracture of the thigh, with perforating gunshot wound. This was a case from the Alma; and on Nov. 22nd, the bone was firmly united, making a useful limb, without the use of splints; the external wounds healed about the same time. No. 12.-Wound of leg ; doing well. No. 13.-Upper third of tibia shattered into pieces, with a large opening, many pieces of dead bone exposed; the fibula left entire, and keeping the leg in its proper form.-Nov. 25th: Circular amputation of the thigh.-29th: Dead. No. 14.-Compound fracture of the upper arm, with three penetrating wounds; severe injury of the elbow; and a perforating wound of the upper part of the chest. This injury was sustained on Sept. 20th; the man appeared likely to do well. No. 15.-Perforating bayonet wound of the thigh; doing

The fact that this Symposium has been arranged to discuss the way in which the food .~ we take can influence the development and calcification of our teeth is an indication that there are still many gaps in our knowledge. It is a subject that has attracted many research workers and a mere review of all the work that has been done on this highly complex problem would fill several volumes. I n a short paper I can only attempt to deal with a limited field and record in a few words the results of work that may have taken months or years of arduous labour and much imaginative thought.The human species is not a good medium to use for any controlled experiments, especially when they have to be carried on over a long period of time, and most of the knowledge we have regarding the effect of various diets upon the calcification of bones and teeth is the result of investigations carried out upon animals that develop more quickly and can be killed at the appropriate time and so provide an opportunity for a detailed examination of the tissue being investigated. There is, however, a good deal of evidence that often the results obtained in one species are not valid for another and a good deal of caution must be exercised in applying the results of animal experiments to the human race and in assuming that the reactions would be the same. In spite of the volume of work that has been done and the valuable information gained from animal experiments, we have little definite knowledge regarding the way in which calcification in man is affected by the various factors in his diet, and when I settled down to the task of trying to present a picture of it I found myself with a very large canvas but very little paint.It is generally agreed that once teeth are calcified and erupted into the mouth the enamel is capable of little change and any effect diet may have upon the breakdown of enamel, as found in that ubiquitous disease dental caries, must be due to local action in the mouth rather than to any effect it may have as the result of metabolism in the body. The way, however, in which enamel is destroyed by local factors, such as food, saliva and the organisms they support, is still far from being understood but, whatever the line of attack, I think it is reasonable to assume that the resistance of a tooth to any attack will be influenced by the way it has developed and the extent to which calcification has taken place. It is to those factors in the diet that are more specifically related to calcification that I propose referring in this paper. 54