In my last lecture I endeavoured to explain the reasons why no one of the present theories of insanity was able to account for all the varieties of the disease. I founded this opinion partly upon the nature of the disorder itself, and partly upon our ignorance of the manner in which the minute internal structure of the brain and cord is altered by the symptoms, and partly upon the uncertain light which the present state of science throws upon the subject, and I pointed out the manner in which I hoped that future investigations might aid us in solving this difficult problem. In my present lecture I propose to speak of the morbid anatomy.