DERMATOLOGY

or proliferative processes. Of such, one may take as an example pemphigus foliaceus. (2) What is the explanation of the apparent retention of nitrogen1? If stored up in the substance of the skin, great increase in its thickness must have been noticeable, yet this did not happen. It is most improbable that there could be some abnormal form of excretion apart from the skin. Tidy believes that the observed retention of nitrogen is apparent and not real, and is accounted for bv loss from the affected skin. (3) Does the retention of nitrogen continue in cases of psoriasis after scaling has ceased 1 Since it is extremely difficult to establish nitrogenous equilibrium in man, it is impossible to draw conclusions from small retentions of nitrogen, and the inference is legitimate that there is no evidence of retention of nitrogen in psoriasis after the disappearance of the eruption. On the very low protein diet which the authors employed in some instances, often combined with low caloric value, the metabolism must be influenced by two factors, namely, the presence of psoriasis, and the conditions of partial starvation.