Attempts to standardise the terms of psychological diagnosis used in asylum admissions triggered a series of debates on psychological classification amongst psychiatrists that commenced in 1864 and continued until 1881. The debates were fuelled over quibbles in terminology, the definitions of terms in proposed diagnostic frameworks and broader differences on the most appropriate philosophical grounds for a clinical classification. The debates outlined in this chapter chart the clash between the symptom-based descriptions of mental disorder that had become dominant with the transmission of French approaches to classification, and a physicalist view that is most clearly seen through the work of David Skae. Skae would come to be the figurehead for a movement that was determined to re-establish the Table of the Forms on the foundations of bodily causes. This chapter analyses the first series of debates over the most appropriate classification for use in asylum medical statistics. These were between those who considered the classification of aetiology developed by Skae to be superior in scientific value to the forms of melancholia, mania and dementia then in use. The debates were split between those who wanted his classification to become used in asylum statistics, and those including James Crichton-Browne who were sceptical about the scientific value of the aetiologies Skae had provided.