THE

SCIENCE NOTES.

ANIMAL AND VEGETABLE CO-PARTNERSHIP.

HE difficulty of distinguishing between animals and vegetables does not appear very great when we compare a cow with a cabbage, or a pig with a rose-bush. Nevertheless, this difficulty is really considerable. The old and still the popular distinction that defines vegetables as fixed to the ground, while animals have the power of locomotion, has been quite given up by naturalists, since they have discovered a multitude of microscopic plants that swim in the most fish-like fashion through the waters, and seeds that walk the earth, and even bury themselves in suitable places by their own vital efforts.

A much later distinctive definition of an animal is that it is a creature having a stomach and able to digest solid food; but this has been disturbed by further investigation of the proceedings of carnivorous plants, which not only catch flies, &c., but actually eat and digest them, by secreting a gastric juice similar to our own.

The general tendency of the modern progress of biological classification has been towards throwing into the vegetable kingdom a number of creatures formerly described as animals. The changes that have been made within the limits of my own recollection—¿.e., since I attended the Edinburgh lectures on natural history by Professor Jamieson-are very remarkable. The great text-book for the microscope in those days was Pritchard's " Infusoria." Turning to that, I find therein engravings of hundreds of species of "animalculæ," or "infusorial animals," that are now classified as vegetables. Even the monad of Buffon, which I was taught to venerate as the fundamental primary of all animals, and his more complex and agile cousin, the beautiful volvox globator, are now regarded as vegetable cells. All the navicula or ship-shaped "animalcula " of the period have become vegetables, bearing the general names of diatomacea and desmidica.

There are many reasons for this, the chief being that they contain starch and that they breathe as plants do-ie, they dissociate the

elements of carbonic acid gas, taking the solid carbon to form their own bodies, and giving off the oxygen to the air-while animals do just the opposite; they oxidise the carbon supplied to them by vegetables, thereby reconverting it to the carbonic acid from which the vegetables obtained it. Thus the animal and vegetable functions are complementary to each other.

It is a curious fact that the fluids which perform these complementary operations have complementary colours-the red blood of the animal and the green chlorophyll of the vegetable. There are, however, some pale pink-blooded animals and pale yellowishjuiced plants. The respiratory functions of both appear to be proportionally weakened.

Besides these, there are certain animals that have green flesh containing a liquid corresponding to blood, but green instead of red. Our sea anemones afford a familiar example of these. The most abundant on our coasts is the smooth anemone (actinia mesembryanthemum). I have gathered these of all colours, from chestnut to bright crimson and scarlet, through dirty reds, due to green admixture, on to bright green and thence to pale sea-green. The strawberry anemone is bright red with bright green or yellow spots; but the most brilliantly green of all is a somewhat different animal in structure, though shaped like the actinia. It is the anthea, also rather abundant on our coasts, especially at Jersey. One variety spreads out tentacles of the richest emerald green, with tips of bright rose pink.

Recent experiments have shown that these creatures expire oxygen after the manner of vegetables; and further investigation has led to the conclusion that this is done by vegetable cells contained within the animal, which cells have a life independent of the animal, as proved by their separability from the animal, and their survival for sone days after its death. The green cells have even been transplanted from one animal into the body of another, where they have survived and multiplied.

They thus appear to be parasitic, but quite unlike those destructive vegetable parasites with which other animals are infested. The internal vegetable cells above described (endodermal unicellular algæ, to which Mr. Geddes proposes to apply the generic name Philozoon) seem to assist the animal by supplying it with oxygen for respiration, while the animal in turn supplies its partner with the carbonic acid it requires a curious instance of biological co-operation or "symbiosis" (living together).

I have named the above well-known animals as illustrations, but VOL. CCLII. NO. 1817.

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similar observations have been made on many others standing on a similar level in the scale of life.

GRANNY.

THE

HE curious partnership between animal and vegetable life described in my last Note may help to account for the remarkable tenacity of life and the prolific powers of the animals which thus give and take their respiratory food independently of outside supplies.

Fifty-three years ago, Sir John Dalzell gathered a well-grown matronly specimen of the common smooth sea anemone from the rocks of North Berwick, and transplanted her to a suitable aquarium. There she outlived her patron, and at his death was bequeathed to the care of Professor John Fleming; afterwards to Dr. James McBain, who, when he found his end approaching, sought another guardian, and after the trust had been declined by some to whom he offered it, found at last a willing and worthy successor in Mr. Sadler, the curator of the Royal Botanic Gardens at Edinburgh. Last year the venerable actinia mesembryanthemum, whose personal name, "Granny," is more distinctive and pronounceable, was alive and "as well as might be expected," seeing that she had brought forth twenty-seven baby actiniæ, all alive and well, during the previous summer. In 1857, when Sir John Dalzell was still her nurse, she gave birth to 240 in one night.

Not having heard any bad news, I suppose that she is still alive, and having survived unchanged for so many years, there is fair prospect of her outliving many more generations of human curators.

In the course of a very large number of experiments in compounding an artificial imitation of sea-water, I have used these animals as my tests, and have discovered that the first symptom of serious illness has been the ejection of a multitude of little actiniæ, with a single ring of tentacles. If this continue, the parent shrivels and then gradually dies-so gradually that one portion may be quite putrid while the other still lingers on alive.

The young are ejected from the mouth of the parent, and soon fix themselves to any convenient rock, but I have never been able to rear them in an aquarium. They somehow disappear. They vary from about 4th to 4th of an inch in diameter across the circle of the tentacles. They may be seen living and growing inside the parent of the greenish and more transparent varieties.

I have never seen an anthea thus produce young, but have had

cases of increase by subdivision; a single animal splitting into as many as six in less than a week.

This splitting is a curious process, the complete animal being a stomach surrounded by tentacles which proceed from a circular wall and base of flesh divided into compartments corresponding to the tentacles. Each half has, therefore, to complete itself by uniting its severed walls and forming a complete stomach of its own.

In the case above mentioned, five of the six fragments did this, but the sixth failed, the tentacles rotting one by one, the last retaining its vital movements until decomposed.

This remarkable vitality of detached tentacles of the anthea has often surprised me. I have watched them for days, wondering how they could survive without the central stomach which forms so important an element of the anatomy of the normal animal.

The investigations described in the preceding note suggest a clue to this mystery; especially as the most remarkable fragmentary vitality was observed in the anthea viridis, or bright green variety.

As

THE VICTORIA REGIA OUTDone.

S the season for visiting Kew Gardens is now approaching, I venture to direct the attention of my readers to some life-sized drawings of a gigantic Aroid, discovered by Beccari in West Sumatra. It is the largest known herbaceous plant of single year's growth. The underground tuber is five feet in circumference. A single leaf from this has a stem ten feet high, dividing into three branches, each as thick as a man's leg, and the segments of the much divided leaf cover an area of forty-five feet in circumference. The flower is of corresponding magnitude. If a living specimen of this could be obtained and grown at Kew or Regent's Park, the departure of Jumbo would be avenged.

A

THE BEGINNINGS OF LIFE ON THE EARTH,

MATHEMATICIAN with a "handle" to his name may venture with impunity to promulgate hypotheses which would at once consign minor mortals to the limbo of "paradoxers." This was glaringly shown when Sir William Thomson, in his inaugural address to the British Association in 1871, enunciated his famous hypothesis, "that life originated on this earth through moss-grown fragments from the ruins of another world." To have stated, as he did, that "we must regard it as probable in the highest degree that there are countless seed-bearing meteoric stones moving through

space" as fragments of a shattered world, was a most heroic speculative venture, seeing that we have no evidence whatever of any world of any sort ever having been shattered at all, still less of its having been shattered so gently as to permit its fragments to travel about bearing uninjured seeds.

The old theory which ascribed the asteroids to the fracture of a large planet has been long since disproved by the distribution of their orbits.

We marvel at the mummy wheat so long preserved amid careful enfoldings in the pyramid; but what is a few thousand years to cosmic periods? and what must be the hardihood of seeds that could exist all this time in vacuous space and still retain the aqueous constituents essential to their vitality?

Besides possessing this vitality, they must have been absolutely fireproof to have endured the heat which we now know, and also knew in 1871, is developed by the collision of meteoric bodies with our atmosphere.

Sir William Thomson has now a rival in Professor Hahn, of Berlin, who has written a book, illustrated with many plates, to prove that certain meteors contain the skeletons of sponges, corals, encrinites, &c., &c. The maintenance of such calcareous and siliceous skeletons, if formed, is conceivable, the conditions under which their existence as mere fossils may be maintained being so different from those demanded by a living germ.

But even these are evidently illusions, as Carl Vogt, Professor Lawrence Smith, and others have shown. They are well-known crystalline structures that have been observed and described again and again by mineralogists, many having specific names that I need not here repeat.

Even when dealing with the minerals of our own globe, we come to structures that are very equivocal. The Eozoon Canadense, the "creature of the dawn," which is commonly described as a sort of geological Adam, the beginner of life on our globe, has been ascribed by able observers to siliceous minerals, "simply affected by partial erosion and replacement, having become shaped into a variety of residual conformations that have been mistaken for organic structures."

The Eozoon controversy has been maintained in a very lively fashion since 1855, when W. King, Professor of Mineralogy and Geology, and Dr. Rowney, Professor of Chemistry in Queen's College, Galway, proclaimed the above-stated heresy. Dr. Carpenter has warmed the discussion by his characteristic description of the