It has been affirmed by Crivelli and Maggi[6] that they have actually seen the particles within granular epithelial cells (taken from the back of the tongue of a patient suffering from diabetes) grow and elongate, so as to give rise to _Bacteria_, or fuse in longitudinal series, so as to form a _Vibrio_.[7] And, moreover, as I have myself ascertained, if one takes healthy-looking epithelial scales scraped from the inside of the mouth, which appear to contain nothing but the finest granules, and places them with a little saliva in a “live-box” (and this within a damp chamber kept at a temperature of about 90° Fahr.), in the course of from 5 to 10 hours, the cells may be found to be studded throughout with motionless _Bacteria_. Of course it may be said that the granules originally seen in the cells were offcasts from pre-existing _Bacteria_[8] which had gained access to the cell. And although, to many, this may seem an extremely improbable supposition, it is, nevertheless, one which it would be very difficult to disprove. The improbability of the notion is increased, moreover, when we find that _Bacteria_, and even _Torulæ_, will develop just as freely within closed cells taken from the very centre of a vegetable tuber, as they will in the midst of the more solid epithelial cell from the inside of the mouth. If it be urged that in this latter situation, there is the greatest chance of the cells being brought into contact with _Bacteria_, and that it must be considered possible for imaginary minute offcasts from these _Bacteria_ to make their own way into the substance of the epithelial cell, I am quite willing to grant the desirability of taking such possibilities into consideration. But, at the same time, it seems all the less likely that the actual occurrence of the _Bacteria_ is explicable on these grounds, because we find them developing just as freely within the cells freshly cut from the centre of a tuberous root, or we may find them already developed within these cells, if the root has begun to decay. To suppose that actual germs of _Bacteria_ and of _Torulæ_ are uniformly distributed throughout the tissues of higher organisms, is to harbour a hypothesis which would appear to many to be devoid of all probability--more especially when the heterogenetic mode of origin of larger and higher organisms is a matter of absolute certainty. [6] Rendiconti del R. Istit. Lombardo, Ser. II. Vol. 1, p. 11. [7] However novel such a mode of origin of independent _Bacteria_ and _Vibriones_ may appear to some, it will seem much less strange and unlikely to others who have seen, as I have done, an _Amœba_, or an _Actinophrys_-like body, originate from the progressive molecular modifications taking place in a mass of chlorophyll and protoplasm within the filament of an alga. Many independent observers have watched all the stages of this process, and some have even seen Ciliated Infusoria originate by such a metamorphic change.