Tuesday, 22 November 2016

"The human side of science"

In Glaucus, his book about the sea shore, Charles Kingsley writes [1]:

 ..few or no writers on Natural History, save Mr. Gosse, Mr. G. H. Lewes, and poor Mr. E. Forbes [who had died in 1854, at the age of 39], have had the power of bringing out the human side of science, and giving to seemingly dry disquisitions and animals of the lowest type, by little touches of pathos and humour, that living and personal interest to bestow which is generally the special function of the poet..

Certainly, both Gosse and Lewes were respected for their detailed, objective observations that we still value today, but, as Kingsley and many others discovered, they were also able to convey their enthusiasm for what they saw. However, they were not always in agreement. While recognising the importance of Gosse in popularising Natural History, Lewes challenged him over an observation on the defence mechanism of some sea anemones, to which Gosse responded (without mention of Lewes' criticism).

The events were these.

George Henry Lewes (above, upper) is less well known than his partner George Eliot (Marian Evans), justly famous as one of the finest novelists in the English language. She was encouraged in her writing by Lewes who was a polymath and, before Marian's success, was himself recognised as a scholar and biographer. Although fascinated by Natural History and Marine Biology, he was accused by T. H. Huxley of being a "book scientist" [2] and this spurred Lewes, accompanied by Marian, to collect, and observe, sea-shore life at Ilfracombe, Tenby, The Scilly Isles and Jersey. He wrote up his findings in Blackwood's Magazine in 1856 and 1857 and these accounts were then re-written, with additions, in his book Sea-side Studies at Ilfracombe, Tenby, The Scilly Isles, & Jersey, also published by Blackwood [3]. The choice of the first locations must have been influenced by Philip Henry Gosse (above, lower) who gave detailed descriptions of both Ilfracombe and Tenby in two of his earlier books [4,5].

Lewes makes reference to the work of Gosse throughout Sea-side Studies and acknowledges the usefulness of his scientific works and the importance of his more general, descriptive books in Marine Biology and microscopy [3]. However, Lewes takes Gosse to task on one point: the role of acontia. These are threads found in some sea anemones and they can be projected through the mouth and from pores in the body (see images below - courtesy of www.aphotomarine.com). This is what Lewes wrote [3]:

Mr Gosse proposes to establish a new genus, named Sagartia.. ..including in it all those Anemones which.. ..possess an abundance of peculiar white filaments, visible to the naked eye, which are protruded from the pores of the body and the mouth, when the animal is roughly handled. These filaments are seen, on examination to be chiefly composed of "urticating [stinging] cells."..
..[Gosse] relates that he once saw a small fish in the convulsions of agony, with one of these filaments in its mouth; it shortly expired. It is a matter of surprise and regret that Mr Gosse, having once made such an observation, did not feel the imperative necessity of repeating and varying it, so as to be sure that death was not a mere coincidence. If the filament had the power which this single observation fairly seemed to suggest, nothing could be easier than to establish the fact by experiment. But, I repeat, no one has seen the necessity for the verification of an hypothesis so plausible; and Mr Gosse, like all his predecessors, was content with recording his observation, as if it carried the point. Not being so content, I tested it thus: After irritating a Dianthus till it sent out a great many filaments, I dropped a very tiny Annelid among them, and entangled it completely in their meshes. Yet lo! these filaments, which are said to possess so powerful a faculty of urtication that even vertebrate animals are killed by them, had no other effect upon a soft Annelid than that of detaining it in their meshes, from which it shortly freed itself and wriggled away unhurt.

Lewes was right to criticise if a general conclusion was being made from a single observation, although his manner of expression is a little blunt. Gosse must have read this and he describes his own experiments on acontia in Actinologia Britannica [6]:

With a razor I took shavings of the cuticle, from the callous part of my own foot, as from the ball of the toe, and from the heel.. ..I then irritated a S. parasitica till it ejected an acontium and taking up with pliers [a] shaving of the cuticle, allowed it to touch the acontium, which instantly adhered across its surface. I now drew away the cuticle gently, so as not to rupture the acontium, and examining it.. ..immediately saw dense groups of cnidæ [stinging threads], standing endwise on the surface,.. ..all discharged and inserted into the substance..

..As to the injection of a poison, it is indubitable that pain, and in some cases death, ensues even to vertebrate animals from momentary contact with the capsuliferous organs of the ZOOPHYTA.

Gosse then refers to the observation criticised by Lewes:

I have elsewhere recorded [in The Aquarium [7]] an instance, in which a little fish, swimming about in health and vigour, died in a few minutes with great agony, through the momentary contact of its lip with one of the emitted acontia of Sagartia parasitica. It is worthy of observation, that, in this case, the fish carried away a portion of the acontium sticking to its lip; the force with which it adhered being so great, that the integrity of the tissues yielded first.

..in the experiments which I have detailed above, we have seen that this adhesion is effected by a multitude of [stinging threads], whose barbs resist withdrawal. So.. ..we can with certainty associate the sudden and violent death of the little fish with the intromission of barbed [stinging threads].

There it rests. What both Lewes and Gosse describe is a fascinating defence mechanism rather than a means of obtaining food. It is something that makes one wonder and to ask "How did that evolve?". Gosse, however, would explain it as an example of God's extraordinary Creation. In contrast, Lewes was an agnostic, so the publication of Darwin's Origin of Species in 1859 will have set his mind on trying to answer the impossible, yet fascinating, questions that we face today. There were many similarities between Lewes and Gosse, but clearly some important differences, and I'm not sure that they would have enjoyed each other's company, especially after the tone of Lewes' criticism. Perhaps I'm wrong?

[1] Charles Kingsley (1855) Glaucus; or, The Wonders of the Shore. London, Macmillan and Co.

[2] Ann Thwaite (2002) Glimpses of the Wonderful: The Life of Philip Henry Gosse 1810-1888. London, Faber and Faber.

[3] George Henry Lewes (1858) Sea-side Studies at Ilfracombe, Tenby, The Scilly Isles & Jersey. Edinburgh, William Blackwood and Sons.

[4] Philip Henry Gosse (1853) A Naturalist's Rambles on the Devonshire Coast. London, John van Voorst.

[5] Philip Henry Gosse (1856) Tenby: a sea-side holiday. London, John van Voorst.

[6] Philip Henry Gosse (1860) Actinologia Britannica. A history of the British sea-anemones and corals. London, John van Voorst.

[7] Philip Henry Gosse (1854) The Aquarium: an unveiling of the wonders of the deep sea. London, John van Voorst.

Thursday, 10 November 2016

Huxley's Bathybius – an early example of an organic aggregate

In a 1983 paper, the oceanographer Tony Rice offers an explanation for the appearance of Bathybius haeckelii, thought to have been a living organism by T.H.Huxley [1]. Rice writes [2]:

In the 100 years or so since Huxley's Bathybius was relegated to the status of an interesting but embarrassing error, knowledge of deep-sea biology has increased enormously, for many thousands of samples both from mid-water and from the deep-sea floor have been collected and examined. Consequently, although the deep ocean is still the least well-understood environment on earth because of its relative inaccessibility, some basic facts about its biological processes are now well-established...
.. With the exception of the minor local input from the activities of chemo-autotrophic bacteria, the food supply on which all deep sea animals are ultimately dependent originates in the near surface layers. In temperate waters, at least, the surface productivity is very seasonal, being highest in spring and summer when the phytoplankton is growing rapidly, and very low during the winter months. Although some of this material reaches the sea floor in the form of large, fast-sinking carcasses of fishes and whales, the main supply probably arrives as small particles, including the bodies of small plants and animals and faecal pellets, which may take many weeks to sink through the water column.

We now know that the sinking material also contains large numbers of flocs and other aggregates bound by the exudates of both bacteria and algae [3]. It is these that give the appearance of fluff that can be found over the ocean floor and which are difficult to collect in dredges, but which are clearly visible in sediment traps [2].

All this is a bit technical.

In the simplest terms, what Huxley observed was a large floc that contained components from near-surface organisms; the conclusion of contemporary scientists being that it was a precipitate of calcium sulphate, caused by preservation of a sample of sea bed in alcohol. This put an end to questions about the organic matter that was also present and the our seeming need to focus on organisms, rather than on total organic matter, was also a problem. We continue this focus, rather than taking the whole package of living and dead organic matter into account.

Let me give an example. What do you see when you look at this image from NOAA [4]?

Most will see an interesting creature – a whiplash squid – and wonder about its biology and mode of life. What about all the white dots in the rest of the picture, illuminated like the particles visible in the beam of a cinema projector? Don't  these raise questions?

While we know more about these particles and aggregates than we did when Tony Rice wrote his article, we still tend to ignore them in favour of our interest in organisms. It is true that the organic matter present in oceans, and other water bodies, is largely dependent on organisms for its production [3], but we must always consider the whole organic, and inorganic, package when trying to understand the biology of water bodies. What a pity that way of thinking didn't start with Huxley's observations on Bathybius.  

[2] A.L.Rice (1983) Thomas Henry Huxley and the strange case of Bathybius haeckelii; a possible alternative explanation. Archives of Natural History 11:169-180.

[3] Roger S. Wotton (2005) The essential role of exopolymers (EPS) in aquatic systems. Oceanography and Marine Biology: An Annual Review 42:57-94.

Wednesday, 9 November 2016

Huxley's error

The popular image of Thomas Henry Huxley (above) is as "Darwin's Bulldog", after his strong support for evolution in a debate with Bishop Wilberforce of Oxford. He was, of course, a distinguished scientist and Natural Historian, all the more surprising as he had little formal school education. However, Huxley was dedicated to reading and to "improving himself" and was eventually accepted to study Medicine, although he didn't complete a degree. This medical training was sufficient for him to be appointed assistant ship's surgeon on H.M.S. Rattlesnake and this gave him the opportunity to study Natural History while at sea, an interest he maintained. Like others at the beginning of the 19th Century, he used microscopes to reveal otherwise unknown organisms and he discovered Bathybius haeckelii. This was subsequently shown to be an artefact, which caused some to deride Huxley. Not me. I admire his courage in admitting his error and in openly facing the consequences.

This is the story.

Huxley writes [1]:

In the year 1857, H.M.S. "Cyclops", under the command of Captain Dayman, was despatched by the Admiralty to ascertain the depth of the sea and the nature of the bottom in that part of the North Atlantic in which it was proposed to lay the telegraph cable, and which is now commonly known as the "Telegraph plateau."

Later in the article, Huxley describes possible organisms that he found [1] and:

..[the] structure to be observed in the gelatinous matter of the Atlantic mud, and in the coccoliths and coccospheres [found there]. I have hitherto said nothing about their meaning, as in an inquiry so difficult and fraught with interest as this, it seems to me in the highest degree important to keep the questions of fact and the questions of interpretation well apart.

Note how Huxley stresses the need to separate fact from interpretation. However, it was in the interpretation of what he observed that an error crept in. Despite his caution, he goes on [1]:

I conceive that the granule-heaps and the transparent gelatinous matter in which they are imbedded represent masses of protoplasm. Take away the cysts which characterise the Radiolaria, and a dead Sphærozoum would very nearly resemble one of the masses of this deep-sea "Urschleim," which must, I think, be regarded as a new form of those simple animated beings which have recently been so well described by Haeckel in his "Monographie der Moneren." I propose to confer upon this new "Moner" the generic name of Bathybius, and to call it after the eminent Professor of Zoology in the University of Jena, B. Haeckelii.

After this, Bathybius (see below) was discovered in other samples of marine mud and it was concluded that it had a world-wide distribution. Furthermore, it gained the status of being a link between non-living and living matter [2,3]. Darwin's theory of evolution had inevitably raised questions about the earliest forms of life and Bathybius fitted that niche. Huxley's initial observations were made two years before Darwin published On the Origin of Species, yet the naming of the organism came nine years after the publication of that hugely important work.

Other Natural Historians were sceptical of the validity of Bathybius. In 1873, Wyville Thomson published The Depths of the Sea describing dredging cruises made by H.M.S. Porcupine and H.M.S. Lightning in 1868-70:

I feel by no means satisfied that Bathybius is the permanent form of any distinct living being. It has seemed to me that different samples have been different in appearance and consistence; and although there is nothing at all improbable in the abundance of a very simple shell-less "moner" at the bottom of the sea, I think it is not impossible that a great deal of the "bathybius", that is to say the diffused formless protoplasm which we find at great depths, may be a kind of mycelium – a formless condition connected either with the growth and multiplication or with the decay – of many different things.

G.C. Wallich had suggested that some of the components of Bathybius were settled fragments from higher in the water column [2] and the living nature of the organism was further criticised in a letter that Wyville Thomson wrote to Huxley in 1875 after another dredging cruise [5]. These two extracts are from Huxley's note on this letter in Nature [5]:

Professor Wyville Thomson further informs me that the best efforts of the "Challenger's" staff have failed to discover Bathybius in a fresh state, and that it is seriously suspected that the thing to which I gave that name is little more than sulphate of lime, precipitated in a flocculent state from the sea-water by the strong alcohol in which the specimens of deep-sea soundings which I examined were preserved..

..Professor Thomson speaks very guardedly, and does not consider the fate of Bathybius to be as yet absolutely decided. But since I am mainly responsible for the mistake, if it be one, of introducing this singular substance into the list of living things, I think I shall err on the right side in attaching even greater weight than he does to the view which he suggests.

With that, Huxley admitted his earlier mistake but, after his prominent role in championing the views of Darwin, he continued to receive disapprobation from those who opposed them. Rehbock [3] quotes one of these:

Huxley's folly was utilized, with similar intent, by William Mallock, the writer and theologian, in 1890. Mallock's article solicited a delightfully typical response from the "bishop-slayer," who was by then feeling some exasperation. This reply is the last recorded event in the history of Bathybius in which its creator took part:

Bathybius is far too convenient a stick to beat this dog with to be ever given up, however many lies may be needed to make the weapon effectual.
I told the whole story in my reply to the Duke of Argyll, but of course the pack give tongue just as loudly as ever. Clerically-minded people cannot be accurate, even the liberals.

This was 15 years after Huxley's note in Nature accepting the likelihood that Bathybius was not an organism and his error is even brought up by some creationists today to try and discredit his views on evolution.

What is clear in the story of Bathybius is the ease by which established scientists can become carried away by current theories, despite a natural caution against speculation. It is as true today as it was in the Nineteenth Century, especially among those who ponder the origins of life, as did Huxley in 1862 [6]:

..the causes of the phenomena of organic nature resolves itself into two problems – the first being the question of the origination of living or organic beings; and the second being the totally distinct problem of the modification and perpetuation of organic beings when they have already come into existence. The first question Mr. Darwin does not touch; he does not deal with it at all; but he says – given the origin of organic matter – supposing its creation to have already taken place, my object is to show in consequence of what laws and what demonstrable properties of organic matter, and of its environments, such states of organic nature as those with which we are acquainted must have come about. This, you will observe, is a perfectly legitimate proposition; every person has a right to define the limits of the inquiry which he sets before himself; and yet it is a most singular thing that in all the multifarious, and not infrequently, ignorant attacks which have been made upon the "Origin of Species," there is nothing which has been more speciously criticised than this particular limitation.

It is thus easy to see Huxley's mind set when he recalled the samples from 1857. Yet both Huxley and Wyville Thomson were on to something when they stressed the importance of organic matter on the ocean floor, as we were to discover years later.

[1] T.H.Huxley (1868) On some organisms living at great depths in the North Atlantic Ocean. Quarterly Journal of Microscopical Science 8:203-212.

[2] Nicolaas A. Rupke (1976) Bathybius Haeckelii and the psychology of scientific discovery. Studies in History and Philosophy of Science 7:53-62

[3] Philip F. Rehbock (1975) Huxley, Haeckel, and the Oceanographers: The Case of Bathybius haeckelii. Isis 66:504-533.

[4] C. Wyville Thomson (1873) The Depths of the Sea. London, Macmillan and Co.

[5] T.H.Huxley (1875) Notes from the "Challenger". Nature 12:315-316.

[6] T.H.Huxley (1862) On our knowledge of the causes of the phenomena of organic nature. London, Robert Hardwicke.