My experience with frozen sections enables me to offer the following directions for making them. First, be very sure that the body, or part, to be frozen is in precisely the position you desire, and that there are no folds or indentations in the skin. I always use natural cold when possible. Weather much about zero (Fahrenheit) is unsatisfactory; but if the part is thoroughly chilled by several days' exposure to a pretty low temperature, a night of 10° may possibly finish it. Salt and ice, or snow, no doubt, will answer the purpose, but much time and patience are required. It is essential that the melted ice should have a chance to run off. The body should be frozen like a rock—so much so that the operator cannot tell whether he is cutting bone or muscle. Tooth is the only tissue he should be able to recognize. The sections should be made in a cold room, with a very sharp saw that has been chilled. When a section is cut, its surface is obscured by a thick half-frozen saw-dust, which is doubly thick if the freezing is not quite sufficient. It is wisest, if time allows, to remove this at once, which is done by pouring a little hot water over the section and brushing or scraping it off rapidly and carefully. This is a very delicate part of the process, and its successful performance has much to do with the beauty of the specimen. If it is to be kept, it should be laid on a piece of glass or wood, and placed at once, while still frozen, in cold alcohol.