Some of these Germs seem to have a short life and rapid development, and then we have acute disease. Others seem to have a more prolonged or continuing career, and then we have chronic disease. Whilst others seem to have an intermitting development, and then we have paroxysmal disease.
Many curious facts have been observed in reference to the forms, or multiplication, or life-history of some of these parasitic beings. Thus, for example, in one class (_Filaria sanguinis_) it was noticed that the minute embryos of this little blood-worm could only be discovered in the evening or during the night, and not during the day; and the reason of this has appeared to be that it is necessary that they should come within reach of the Mosquito Gnat, which is a night-feeding animal, in whose bodies one stage of their development appears to take place.
One of the latest discoveries in this department of natural history is that of the blood germs, which co-exist with the various forms of ague and malarious disease, and upon which they would appear to depend. Dr. Osler, of Pennsylvania (now Regius Professor of Medicine, at Oxford), has recently described and figured these little bodies in an elaborate paper full of interest.
Such facts as these, when regarded merely from the point of view of a member of the Medical Profession have their deep and _special_ significance. But I am here to-night as a member of the Naturalists’ Society, and by all of us, in that capacity, they are first to be regarded, not as illustrations of disease, but of the life history of some of nature’s creations—creations which are no doubt as important, as definite, and which play as large a part in the general scheme of life, as do many of the larger forms of animated beings.
Some of these little bodies, especially those of the bacillary and bacterial class, are extremely minute, and are best examined with powers ranging from one-tenth to one-twenty-fifth of an inch; and it is impossible to ignore the fact that their study requires not only good instruments, but much patience and skilled attention. Nevertheless, such study fairly comes within the scope of this Society’s work, and will most certainly repay any of its members who may be induced adequately to undertake it.