4. "=Stimulation forms=" were first described by Türk, and are mononuclear non-granulated cells. They possess a protoplasm staining with various degrees of intensity, but in any case giving with triacid solution an extraordinarily deep dark-brown, and further a round simple nucleus often eccentrically situated, stained a moderately deep bluish-green, with however a distinct chromatin network. The smallest forms stand between the lymphocytes and the large mononuclear leucocytes, but approach the first named as a whole in their size and general appearance. According to Türk's investigations, these cells often occur simultaneously with, and under the same conditions as the myelocytes. Their importance cannot at present be accurately gauged. Possibly they form an early stage of development of the nucleated red blood corpuscles, as the deeply staining and homogeneous protoplasm seems to indicate.
With the description of these abnormal forms of white corpuscles all occurring forms are by no means exhausted. We are here excepting completely the variations in size which particularly affect the polynuclear and eosinophil cells, and which lead to dwarf and giant forms of them. For however considerable the difference in size, these cells always possess characteristics sufficient for an exact diagnosis. But besides these, isolated cells of an especially large kind are found particularly in leukæmic blood, and concerning their importance and relationship we are up to the present in the dark.
[11] In enumerating the blood corpuscles, 2 and 3 may be counted separately or in one group.
[12] The assumption of Czerny, that the cells which react to iodine emigrate from suppurating foci, is without foundation. A simple investigation of freshly inflamed tissue is sufficient to show that the cells which have wandered from the blood stream soon contain glycogen.
[13] Kanthack described this group as "finely granular oxyphil" cells. Their granules stain red in eosine and in eosine-methylene blue solutions, but the colour is different from that of the true eosinophil cells, and much less intense. In the latter mixture they stain really with the methylene blue salt of eosine. Their true nature is shown by their behaviour with the triacid solution.