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No. 21 six and cow No. 26 four. The numbered germs from the last named animals are representative of but three milking dates each. It is thus a possibility, that further milking dates for these cows might have given others of those common to Cow No. 24. While this point last named, is probably a correct consideration, it is nevertheless quite clearly indicated that the great majority of germs are but incidental in a given udder or teat to the date, perhaps, to the environments of the animal. There are, however, certain few germs found which when once present in a teat or udder, remain with marked presistence. For this capability, these are found to possess what are presumably the proper physiological functions or requirements, as for example, capability to properly thrive in or withstand the normal temperature of the animal's body, and anaerobic or semi-anaerobic faculties.

As in the case of the paper previously mentioned, this is given not as final evidence to convince upon the points mentioned or suggested, but rather as a record of preliminary work accomplished.

Again, an interesting fact is the comparatively low number of species per milk sample. In the first work, winter collections, the range was from one to four species, in this it is one to five with a rather high average number. It is also interesting, though perhaps to be expected, that quantitative determinations vary from low to high numbers for different milkings, very much in accord to these last named figures.

North Dakota Experiment Station, Fargo, N. D., August, 20,




The beginning of life upon the earth is one of those mysteries which, to judge from what we now know about it, seems likely never to be solved by ascertained facts. There are mod

ern facts, indeed, which bear upon it, but few geological ones, and none of absolute force. If we leave out of the question the highly problematical "Eozoon Canadense," we find the first known fossils at a comparatively high level in the rocks; and these, instead of being, as the theory of evolution requires, of very simple organization, are of a degree of development which indicates a very long period of preceding life existence. This primeval fauna, indeed, contains representatives of every branch of animal life except the vertebrate, and these not in their simplest stage, but already divided into their principal orders: the Cœlenterate class, for instance, yielding examples of Actinozoa and Hydrozoa; the Crustacean, of Trilobites and Phyllopods; and the Molluscan, of Gasteropods, Lamellibranchs and Pteropods.

This is the beginning of life as we know it. It is very far from the beginning of life as evolution demands, or as the character of the rock strata indicates. Below the Lower Cambrian beds, which contain these fossils, lie several miles of stratified rocks similar in physical character to those above them, and indicating, as Darwin says, "that during a preceding era as long as, or probably far longer than, the whole interval from the Cambrian age to the present day . . the world

swarmed with living creatures."

Evidently we are not yet at the origin of life. We are miles away from it probably-miles of rock strata, that is. Between the simplest known microscopic creatures and the much developed Cambrian fossils an immense gap extends. The gap, for example, between a diatom and an oyster is one that represents ages of evolution; yet it is much less in extent than the yawning gap which we find dividing the line of primeval life, and which geologists have sought in vain to fill. Believers in evolution-who represent about all living scientists and the bulk of living thinkers-cannot but stand in some dismay before this strange circumstance, which must be proved away or explained away before their theory can be fully substantiated. Yet proof is not forthcoming, and only attempts at explanation remain.

In April, 1885, I presented certain views on this subject before the Academy of Natural Sciences of Philadelphia, and reinforced my arguments by later communications in 1885 and 1886. In 1894 Professor W. K. Brooks, evidently unaware of the existence of the papers mentioned, advanced a similar hypothesis in the July-August number of the "Journal of Geology," presenting a number of interesting facts, though missing, as it seems to me, much the strongest argument in defence of the hypothesis.

I propose here to repeat my former hypothesis, with additional arguments and illustrations-for some of the latter of which I acknowledge indebtedness to Professor Brooks's able paper.

To begin with, the facts of embryology may be said to point directly to what was probably the primary condition of life. The embryos of ocean animals, as a rule, begin life as swimming forms. Even the oyster-a type of sluggishness in animals-enjoys a brief existence as a swimmer before it acquires a shell and becomes permanently fixed. The same is the case with the sponge, the coral, and other stationary types, and with the various creeping or slow moving forms, such as the echinoderms. Since it has become a settled dogma of science that each stage of development passed through by the embryo represents some mature stage in the ancient ancestry of the animal, the fact stated points almost irresistably to the conclusion that the far off ancestors of the present stationary or crawling animals were swimmers-and, for that matter, naked swimmers, they being as yet destitute of hard skeletal parts.

Yet no swimming stage of existence is indicated by the oldest known fossils, or at least only by the minute pteropods and phyllopods, which were, perhaps, secondary derivatives from crawling ancestors. The trilobite may have had some swimming powers, yet probably made its way only by crawling, and the other known forms were crawlers or burrowers, or were immovably fixed. There are traces of jelly fish, it is true, but these, as they now exist, we know to be derivatives from stationary forms, and the primeval swimmers indicated by embryology have left no trace of their existence in the rocks.

Yet the oceanic waters to-day swarm with swimming life, and in all probability did so then. This life, as now existing, contains many high as well as numerous low forms. Then it must have consisted of low forms only. The wealth of existing minor sea life, as observed by the unassisted eye and revealed by the microscope, is simply boundless. Small jelly fish are met with in vast armies, hundreds of miles in extent, and descending to many feet in depth. Pteropods, both the

naked and the shelled forms, occur in prodigious multitudes. The minute copepod crustaceans are found in countless swarms, and, though consumed in myriads daily by herring and other fish, by medusæ, siphonophora and other invertebrates, and even by the whale, they are so productive that their numbers seem undiminished, being found over vast areas of surface and extending through more than a mile in vertical depth. Below these again are hosts of microscopic larvæ and minute animals, and still lower are countless swarms of protozoa, such as radiolarians, globigerinæ, etc.

Here, then, are innumerable swarms of swimming and floating forms, in most part carnivorous, but necessarily requiring a vegetable basis of nutriment. The foundation food supply for such a mighty host must be enormous in quantity. The visible plant life of the ocean, the algae which grow on the bottom, would not sustain a tithe of such an army. The microscope must again be brought into requisition, and this useful instrument reveals to us an extraordinary profusion of unicellular plants-diatoms, coccospheres, trichodesmiums, and a few other types-which extend from the surface to the lowest level of light penetration, and are so extraordinarily numerous and prolific as to supply food for all the oceanic host. These, and the protozoa which feed upon them, form the basic food supply for the countless myriads of living forms which compose the fauna of modern seas.

Yet, were the conditions of the ocean as they exist to-day to be sought for by some far future geologic delver into the mysteries of the rocks, almost nothing of this profusion of life would be revealed, discovery being nearly or entirely confined to such forms as possess hard skeletons, internal or external, of

which most of these forms are destitute. The same was probably the case with the period which we now have under review, and of whose life we find few forms except those which habitually dwelt upon the bottom. The ocean may have been as full of life then as it is to-day, many of the swimmers of that period, perhaps, representing the ancestral lines out of which the bottom dwellers had evolved, and which are still in a measure preserved for us in modern embryos. These primeval forms may have been even less suitable for fossilization than their counterparts of to-day. The diatoms, the radiolarians, and other minute existing forms have silicious shells capable of preservation. It is quite possible that the early protozoa and protophytes had no such skeletal parts, and that when they died all trace of them departed.

How far back, then, from the earliest age of fossils must we place the actual date of the origin of life? Ages perhaps― epochs-a period as remote from the Cambrian in one direction as we are in the opposite. It may have taken as long, or longer, to develop the trilobite as it since has taken to develop During the whole of the immensely long period in which the miles of earlier strata were being deposited, the ocean may have been the seat of an abundant life of the lowest type, and this a very slowly evolving one, the conditions being such that competition and the struggle for existence were not strongly active.


Of the forms of life now existing, the most abundant and the lowest in organization known to us are the bacteria or microbes-omnivorous life specks, feeding alike on animals and plants, and fairly assignable to neither. Possibly life had its origin in forms like these, or in still lower stages of protoplasmic activity, and from this condition developed, after an interminable period, into the simple oceanic protozoa and protophytes typified by the radiolorians and the diatoms, the lowest forms having characters common to both animals and plants, while their descendants divided definitely into plants and animals.

The period here referred to, and that subsequently consumed in the development of the trilobite and its companion forms,

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