6. =In malignant tumours.= In the cachexia from tumours an increase of the eosinophil cells has been observed by various authors. It is however of moderate degree and does not exceed 7-10%. Out of 40 decided cases Reinbach found the eosinophils increased only in four, in a case of sarcoma of the forearm he found 7.8%; of the thigh 8.4%; malignant tumour of the abdomen 11.6%. Besides these he describes a case of lymphosarcoma of the neck with metastases in the bone-marrow, in which an unexampled increase of the white blood corpuscles, and especially of the eosinophil cells was found. The absolute number of the latter amounted on one day to some 60,000! This is an increase of 300 fold the normal, which apart from leukæmia has doubtless never before been found.
7. =Compensatory eosinophilia= (after exclusion of the spleen). We have entered in detail into this form in the chapter on splenic function; and have there already mentioned that the increase of the eosinophils found in chronic splenic tumours by Rieder, Weiss and others, must also be referred to the exclusion of the splenic function.
8. =Medicinal eosinophilia.= Under this group occurs only a single observation of v. Noorden's, who observed the appearance of an eosinophilia up to 9% in two chlorotic girls after internal administration of camphor. In other patients this occurrence did not repeat itself. But probably researches specially directed to this province of pharmacology would bring to our knowledge many interesting facts.
On the origin of ~polynuclear eosinophil leucocytosis~ authors have put forward various theories, which we will here critically discuss in succession.
An experiment frequently quoted as explanatory is that of Müller and Rieder's; these authors do not derive the eosinophil cells of the blood from the bone-marrow, but assume, as very probable, that the finely granular cells grow into eosinophils within the blood-stream. This developmental process seems very improbable for many reasons. Since the polynuclear cells circulating in the blood are all under the same conditions of nutrition, it is _à priori_ inconceivable why only a relatively small portion of them should undergo the transformation in question. And it is quite inexplicable why in infectious leucocytosis, where the number of the polynuclears is increased so enormously, their ripening to the eosinophils should remain completely interrupted.