Following continuous and consecutive administration of morphine (and the same is true of other opiates) comes failure to secure the effect which followed the early administration. Larger doses are needed for the relief of pain or other symptoms, or the original doses give relief for a shorter time. Toxic manifestations do not follow what would formerly have been a toxic dose. The patient requires what was formerly a toxic dose to secure the former therapeutic effect. The phenomena of this stage are familiar to every observing clinician who has used or seen morphine used for continued therapeutic action. The patient has acquired an increased tolerance of the drug and a beginning immunity to its toxic action. He does not, however, suffer appreciable hardship from drug deprivation. Discontinuance of the drug causes little or none of the symptoms to be described as “withdrawal signs.” 3. _Stage of Beginning Addiction._ Following the stage of increased tolerance comes a stage where discontinuance or lack of administration of the narcotic drug gives definite signs and symptoms, beginning “withdrawal signs,” due to some beginning physical body demand for the drug and completely relievable only by its administration. These signs are identical with the first appearing withdrawal signs in a case of established addiction but as yet do not go beyond the beginning manifestations of “withdrawal” in a completely developed addiction. They are limited to a peculiar nervousness, restlessness, weakness, depression, etc. They persist for a few days only if the drug is denied and are endurable. As to length of time required for the passage through each of these previous stages or through both of them--dogmatic statement is impossible. The time is apparently influenced by a number of factors. Of course the varying inherent resistance or susceptibility of different individuals to any given disease condition must be considered in this disease. It varies also with different forms of opiates used and their modes of administration. The probable physical factors I am not yet ready to discuss. The recent Report of the Special Committee of the Treasury Department says, “Any one repeatedly taking a narcotic drug over a period of 30 days, in the case of a very susceptible individual for 10 days, is in grave danger of becoming an addict.” Certainly a physician should look for the signs and symptoms of tolerance and beginning addiction throughout his opiate administration. It is also well to exhaustively inquire into possible past history of unrecognized addiction in any of its three general stages. Some of those patients who have demonstrated an apparent unusual susceptibility and very rapid development will be found on careful analysis to have experienced an unrecognized or forgotten addiction in some stage of development. I have interesting data on this point. 4. _Stage of Established Addiction._