In the meantime Ehrlich had made various observations which could not be completely brought into line with his own earlier hypothesis or the far-reaching conclusions of Altmann. Studies in particular on the oxygen requirements of the organism, shewed that the "ozonophores" could certainly not be an important part of the cell. In addition it was found that normally cells occur in which no granules can be recognised by ordinary methods. Finally a pathological observation made untenable the view that the granules are the bearers of the cell function. In a case of pernicious anæmia (cp. _Farbenanalytische untersuchungen_) Ehrlich found the polynuclear cells of the blood and bone-marrow and their early forms free from all neutrophil granulation. On the grounds of this observation Ehrlich returned to his original assumption that the granules are secretory products of the cells, and defined his standpoint at that time as follows:
"Did the neutrophil granulations really represent the bodies which supply these cells with oxygen, as Altmann supposes, a condition such as we have here brought forward would be impossible, since with the disappearance of the granules death of the cells must follow. But from the point of view of the secretion theory the condition described is easily explainable. Just as under certain conditions fat-cells may completely lose their contents without dying, so the bone-marrow cell, if the blood fails to yield to it the necessary substances, may occasionally be unable to produce more neutrophil granules. And thus it becomes non-granular."
The view, that the granules are special metabolic products of the specific cellular activity, is strongly supported by the great chemical differences between them. Ehrlich made these peculiarities clear for the blood-cells, and found that their granulations differ from one another, not only in their colour reactions, but also in their =shape= and =solubility=; so that they must be sharply distinguished.
Whilst for instance the majority of the granules are more or less rounded forms, in some classes of animals, _e.g._ in birds, the analogues of the granules of mammalian blood are characterised by a decided crystalline form, and a strong oxyphilia. The substance of the mast cell granulations is also crystalline in some species of animals.