Documentary News Letter (1947-1949)

DOCUMENTARY NEWS LETTER 69 At the Pasteur Institute in France amazing new techniques are used to him operations on organisms so tiny that they have plenty of room to romp inside the eye of a needle. J. V. DURDEN here gives an expert's view to these new developments in FILMS AND MICRO-BIOLOGY it is a pleasure to see fresh examples of the use of the film as a tool in the hinds of biological research workers. It is with the complexities of the living processes, both in the Stud) of the plant and the animal kingdoms, that the film really comes into its own as the recording medium par excellence. What is even more gratifying is to see the supreme skill with which the difficult problems of cine-micrography nave been solved by Dr. Comandon and M. de Fonbrune o\' the l)epartement de Cinemicrographie of the Pasteur Institute, in the films recentlj presented at the British Council by M. de Fonbrune. The subject of this series of films is Microbiology, the microscopic study of some of the smallest units of living matter. The object of the research was the elucidation of certain littleunderstood phenomena difficult to comprehend by the more normal methods of visual observation. Seven films were shown: ( 1 ) Caryocinese. (2) Amoeba Verrucosa. (3) Phagocytose. (4) Technique de Micromanipulation. (5) Substitution de Noyaux D'Amibes. (6) Champignons I'redateurs. (7) Lankesterella. In the first film we see time-lapse records of the phenomenon of karyokinesis, the reactions of the nucleus during the process of cell division. In living material, as opposed to fixed and stained micro-preparations, the nucleus is, in most cases, by no means easy to see. The time-lapse technique, coupled with brilliant photo-micrography, demonstrates conclusive!; the extreme value of the cinema for this type of investig ttion and record. This sort of thing has beer, done before, notably in the work of the late Dr. (ami and in some of the films photographed by the late Percy Smith; but never has the quality of the result approached these new elforts from 'he workers at the Pasteur Institute. Feeding the Amoeba The second film is an attempt to gain in;. Hon on the mechanism of ingestion of foodparticles b) the single-celled organism amoeba. It had long been thought that the food penetrated the protoplasm of the organism bv some purelv physical means, such as capillary attraction. That this was not so was shown clearly many sears ago in a film b) Percy Smith in which amoeba was shown itself to displa) the most energetic activity in the matter of eating its food, the pseudopodia advancing round and trapping quite active micro-organisms. In this Pasteur film the amoebae were led with quite large algae, man) times longer than the amoebae themselves. I he protoplasm of the amoeba was clearl) shown to exert a considerable force on the alga, appearing to pull it from within as a pseudopodium advanced along it, and coi the threadlike alga up like a spring within the cell: so great was the tension of this spring that. in some instances filmed, it exceeded the cohesion of the protoplasm and burst out of the amoeba on the opposite side to that on which it was ingested. This sudden eruption in no wa) incapacitated the amoeba, which was able immediately to go on feeding on another alga. Blood Football The third film in this series is a spectacular demonstration of the bacteriocidal activities of the white corpuscles in the blood. It opens with a time-lapse shot of blood showing the normal state of the leucocytes in which they wander at random amongst the red corpuscles. Then small aggregates of bacteria are introduced into the blood; immediately the leucocytes cease their aimless wandering and converge on the interlopers like the players converging on the ball on the football field. They ingest the bacteria and then disperse once more. The technique of darkground illumination is particularly good in this film causing the white corpuscles to stand out clearly and in brilliant contrast to the red corpuscles. It should be pointed out that to achieve such a striking picture as is presented here, the blood must be treated so that it contains a higher percentage of white corpuscles than normal. Too Many Clocks It is a pity that the time-lapse sequences in all these films arc marred by the introduction of a clock face recording the degree of speeding-up of the observed action. This device, used many times before, has always been a source of distraction to the viewer and adds nothing to the value of the scene. While realizing that the timing of the recorded phenomena is of vital importance to the research worker, we feel that it would be preferable, and not difficult, to photograph the timing dev ice on the portion of the film normal!) occupied by the sound track so that it would he masked off durin" projection. I Ik Micro Forge I he second part of this extremely interesting Show was devoted to the exposition o\ another specialized technique used in micro-biolo namclv micro-manipulation. It is possible perform delicate operations on microscopic organisms by what is known as micro-dissection. I this work, two ingenious instruments have been devised b) M de Fonbrune, the mi< forge and the micro-mampulatoi ; the former is Kikmu the required tools and the lattei foi using them. Both these instruments were demonstrated in the next film. Unfortunately the filmicexposition was not too good, and one was left with a rather hazy impression of their mechanics and operation. However, the section dealing with the making of the extremely line implements used in micro-dissection, which is actually done under the microscope, was very clear and gave a good idea of the potentialities of the micro-forge. The three remaining films were of subjects which could only be tackled with the help of the micro-manipulator, first came the removal of the nucleus from the liv ing cell of an amoeba, showing the subsequent reactions of the organism; its normal activities are inhibited and it behaves quite irregularly, being unable to move properlv, feed, or reproduce. Nevertheless it remains alive for some considerable time after this drastic operation. More remarkable still is the implanting of another nucleus into a disorganized amoeba w Inch has been deprived of its ow n some hours previously ; incredible though it may seem, the cell recovers and the creature resumes its normal behaviour as if nothing whatever had happened to it. A Strange Fungus A strange soil-dwelling fungus provides the subject for the second example of micro-manipulation. This organism, given the right conditions, develops peculiar rings on its tiyphae with which it can snare minute but active nematode worms, there are not many plants w hich arc carnivorous, and they are all amongst the higher plants ; nevertheless this microscopic and lowly fungus manages to equal their skill in trapping active p It is shown in the film how nutation oi (he inner surfaces of the three cells o\ which the hyphal rings arc composed, causes immediate expansion inwards of the cells then Iting the central aperture o\' the n tation is laced artificially by rubbing with a microneedle. When the same irritation is caused naturally In the nematode entering the ring, the worm is caught bv the sudden constriction of the aperture and is eventually digested. This phenomenon, which one might wan to observe naturally, was brought about for the purposes of the film bv holding the worm micro-pipette and inserting the creature into the deadly noose. I he last film shows the puncturing of the les of the blood li/ed bv the organism lankesterella Die lib* tion o( the parasite is seen. M\d vith which it penetrates the tough envelopes of other corpuscles. I) ( omandon and M de I onbrune are to lv pratulated on their efforts, and it is to be hoped that we shall sec mote work ot the cal of these films in the future