This book, in a sense, is a personal narrative, and necessarily must be so, giving an account, as it does, of observations in experiments upon myself. In making these experiments I have endeavored to treat myself impersonally, as a subject, so to say, placed at my disposal for experimental purposes; my ego having been the object as well as the subject of my investigations. In occasionally speaking of the results thus obtained in a eulogistic manner, this should not be looked upon as self-praise, therefore, but rather as an impersonal mode of describing what has come under some one's observation--this "some one" being myself. I want to place the matters I have observed before the reader in the right light, and do not hesitate to say or fear to say just what I think to be the truth. If I were to wait for others to say these things the reader who does not comprehend their latitude as I do might have to wait a long time before he could grasp the subject in its entire importance. I want to say this much as an apology and a vindication for frequent indulgences in apparent self-eulogism. I have another motive for making such remarks; viz., the desire of rousing the scientific world from its apathy regarding these matters. These laudatory remarks may wound its pride, and possibly arouse its ire,--more especially in view of their coming from a layman,--and thus induce it to study these matters, if but for the purpose and with the view of controverting them. I would hail such an endeavor with pleasure, not having the slightest fear of its ability to successfully controvert any of the vital facts I have ascertained, and whose correctness I expect to prove by a great array of facts with accompanying proofs. When I first began to make these studies, I made numerous notes as new features happened to present themselves to my mind. I have encountered no inconsiderable difficulty in sifting this material so as to present my experiences in as connected and consecutive a manner as possible. In this, however, I have only partially succeeded; nor have I been able to altogether avoid repetitions. For these shortcomings I must plead a want of time. For some time past, however, my experiences have accumulated so rapidly that I have ceased to take any notes whatever, trusting to my memory that these mental notes may be recalled at the proper time. No doubt some things, even of importance, have thus been lost sight of. Still, while pursuing similar studies, they may in the course of time turn up in some one else's mind.