About forty pages of new matter have been added, but the book is no larger than before, as a corresponding number of pages have been omitted from the bibliography. A complete bibliography of the subject would now need a separate volume, and it has therefore seemed best to omit all but the most important references.<br><br>The principal additions to the book include an account of Professor Oliver's tintometer and hæmoglobinometer (which are the only new instruments of importance), new matter in the chapter on the primary anæmias, and on leukæmia, and a description of Müller's "blood-dust" (the newly discovered constituent of normal and abnormal blood). Bremer's and Williamson's tests for diabetic blood and the iodine reaction in the blood during acute surpurative processes are described, and blood exminations are recorded in Malta fever, yellow fever, epidemic dropsy, beri-beri, relapsing fever, tetanus, chickenpox, whooping-cough, and epidemic cerebro-spinal meningitis, diseases not included in previous editions. New observations on poisoning by alcohol, opium, corrosives, and ptomains, on aneurisms, on paroxysmal hæmoglobinaemia, and on cretinism are recorded.<br><br>I have wished to draw especial attention to the tendency to an oval or sausage shape among the red corpuscles in cases of grave anæmia and to the occurrence of adventitious forms of leucocytes in leucocytosis.<br><br>Some of my critics have regretted that there was so little theoretical discussion in the book. In this edition I have for the most part eliminated what little there was before. It had already become out of date.