A study of the blood calcium in 167 cases of asthma and allied conditions is presented in the hope of helping to define the importance of calcium determination and calcium treatment in atopic or allergic conditions. The second part of this paper is a preliminary report on the analysis of the gastric contents in fifty cases of atopy. CALCIUM METABOLISM IN ATOPY A discussion of this phase of the subject is closely related to the various theories explaining the pathogenesis of asthma and of allied conditions. It is a fairly well established fact that these conditions are due to a form of hypersensitiveness either to some extrinsic protein or to an infection usually of the upper respiratory tract. There are those who insist on the reflex origin of asthma, and somewhat associated with the latter theory is the explanation advanced by Pottenger,1 who feels that in asthma there is a