But naturally, the occurrence of non-granulated polynuclear cells in certain classes of animals is not to be denied from these considerations. Hirschfeld asserts that such cells occur side by side with granulated cells, for instance in the dog; and draws from them far-reaching conclusions as to the meaning of the granules. From Kurloff's work (see p. 85) we must insist, on the contrary, that there is no evidence that the non-granulated polynuclears are identical with the granulated cells. Kurloff has shewn, at least for guinea-pig's blood, that these two heterogeneous elements are to be sharply separated one from the other, and that they have an entirely different origin. Specially important for a theory of the nature of the granules is the circumstance, that generally speaking in all species of animals =they are present in those cells of the blood only which are adapted to and capable of emigration=. That a certain nutritive function is to be ascribed to the emigration of the granulated cells is a very obvious supposition, scarcely to be denied; and naturally cells with a plentiful store of reserve material are eminently suited for this purpose. The lymphocytes on the contrary, incapable of emigration, are almost totally devoid of specific granulations. A further indication that =the granulations really are connected with a specific cell activity lies in the fact, that one cell bears but one specific granulation=. The contrary assertions that neutrophil and eosinophil, or eosinophil and mast cell granulations occur in the same cell Ehrlich regards as unfounded, from extensive researches specially directed to this point. Nor has Ehrlich seen a pseudoeosinophil cell of the rabbit change to a true eosinophil[23]. That such a transition does not occur is most distinctly shewn by the fact that the various granulations behave entirely differently towards solvents. With the aid of acids, for example, the pseudoeosinophil granules can be completely extracted from the cells, whilst the eosinophil granules remain whole under this process, and can now be stained by themselves.