THE presence of fascicular contractions in muscle is a physical sign which is of great help to the clinician in reaching a diagnosis. The electromyograph can be used as a delicate tool for the detection of fasciculations not obvious to the eye, for although in some muscles over which the subcutaneous tissue is thin fasciculations if present can be readily observed, in other muscles even when present they escape observation. In some cases the bilateral or diffuse nature of a lesion can be observed earlier by electromyography than by clinical examination. The application of electromyography to the detection of fasciculations in muscles due to lesions of the spinal cord and of the peripheral nerves has been in use in this laboratory1and in others2for some time. In 1944 Hoefer and Guttman2described an electromyographic method for determination of the level of lesions in the spinal cord