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Creator (Definite): Marion Greenwood BidderDate: 1887
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Cited byC.A. Ballance and C.S. Sherrington, 'On Formation of Scar-Tissue', Journal of Physiology 10 (6), (1889), pp. 550-578.
Description:'We doubt whether without very special apparatus the cells of the tissues of mammalia can be kept in sufficiently normal condition for sufficient length of time to compass observations on ingestion by living cells; we were however much assisted in the interpretation of the appearances of the osmic fixed preparations by the processes described by Miss M. Greenwood for the Rhizopoda. Her observations [note: 'This Journal, Vol. VII. p. 253, Vol. VIII. p. 263.'] were conducted on living specimens of Amoeba proteus and Actinosphaerium, and she was able to follow in these animals under the microscope all the visible phenomena accompanying the ingestion of prey. In our preparations we had as it were a number of amoebae, many of which had been actively engaged in ingesting living prey, immediately before the reagent had been used that killed them so rapidly as to allow no time for any great departure from their previous aspect.' (559)
'leucocytes served... as a pabulum for the active plasma-cells [note: 'The plasma-cells are considered by Metschnikoff... ' (note cut short here)]. Just as, in the extremely interesting observations given by M. Greenwood [note: 'This Journal, Vol. VII. p. 253. Vol. VIII. p. 263.'], little monads, Euglenae and Algae coexisting in the same water with Amoeba proteus were by it ingested, so leucocytes become the prey of the plasma-cell, and are by it included and ingested. And if the growth and proliferation of the plasma-cells be of importance in the process of repair, what circumstance more propitious than the presence in abundance of nutriment so delicately adapted and so highly organized as the substance of the leucocytic cell? Of Amoeba and Actinosphaerium it was remarked that the food most suitable to these forms is unshielded non-coagulated proteid matter. A low degree of vitality, a diminished activity of its protoplasm, renders an organism easier prey, more readily captured and more readily absorbed. The plasma-cell may in some respects be taken as a hothouse variety of amoeba; it finds its unshielded non-coagulated proteid in the dead or dying leucocyte.' (568-569)
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Cited byM. Verworn, Allgemeine Physiologie: ein Grundriss der Lehre vom Leben (2nd ed.) (Jena, 1897).
Description:'scheint es nach den ausgezeichneten Untersuchungen von Greenwood [note: 'Greenwood, „On the Digestive Process in Some Rhizopods". In Journal of Physiology vol. VII and vol. VIII, no. 5.'] und Meissner (l[oc]. c[it].), dass Rhizopoden, wie z. B. Amoeben, obwohl sie gelegentlich Stärke in sich aufnehmen, dieselbe doch nicht zu verdauen im Stande sind.
Die Fette endlich werden bei der extracellularen Verdauung durch das Fettferment, das „Steapsin" ebenfalls unter Hydratation gespalten in Glycerin und Fettsäuren, wovon die letzteren sich mit Alkalien zu Seifen verbinden. Glycerin sowie Seifen aber sind löslich und können resorbirt werden. Dagegen findet bei der intracellularen Aufnahme der neutralen Fetttröpfchen als solcher nicht immer eine sofortige Verdauung statt. Wie Meissner beobachtet hat, behalten Amoeben und Infusorien aufgenommene Fetttröpfchen Tage lang unverändert in ihrem Protoplasma, und Greenwood hat gefunden, dass Amoeba und Actinosphaerium das aufgenommene Fett überhaupt nicht verdauen.' (160)
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Quoted by
An Amoeboid Theatre: Marion Greenwood Bidder's physiological research at Cambridge (1879-1899)
Description:'Greenwood’s earliest articles, published in The Journal of Physiology, concerned amoeboid digestion. She described her interest in the digestive processes of amoeba as arising out of the by-then well-known observation that a ‘characteristic’ feature of Rhizopoda was their ‘constant’ ingestion of matter. Whilst many authors had noted the fact that amoeba appeared to ingest material from their surroundings, the processes by which they assimilated it had remained at the margins of histological discourse.'
'Noting in an article on the Rhizopods the existence of ‘but few descriptions which deal at all fully with the mode of ingestion, and fewer which give in detail the changes taking place in ingested bodies’, Greenwood implicitly aligned herself with the founding figures of histology. Her commitment to the investigation of cellular activity would lead her to participate in the constitution of a then-emerging conception of amoebae not as inert bodies or substance-producing factories, but as animals species in their own right – as species that could be distinguished by their district activities as well as by their fixed anatomical states.'
'Greenwood's principal interest in her amoeboid actors in these did not concern the relationships that they had to one another, but rather the conditions under which they were able to thrive. Central to this concern was consideration of the means by which they assimilated matter from their surroundings. As she noted, though a range of scattered observations existed on the incorporation of outside matter by very simple organisms (most of which took their cue from Christian Gottfried Ehrenberg's famous contentions regarding the presence of 'stomachs' in 'polgastric infusoria'), there had been no systematic study of the processes of amoeboid digestion.'
'Whereas histological anatomists 'fixed' cells to their slides as a prelude to colouring them with stains, thereby killing them in the process, Greenwood would encourage her objects of study to assimilate coloured matter whilst they were still alive. She portrayed this strategy as having emerged during a chance observation, during which an amoeba formed a vacuole around 'a Monad... and a green Protococcus' (a type of algae, coloured green by chlorophyll). Over a period of six hours, Greenwood had watched the incorporation of the Protococcus into the body of the amoeba, at the end of which the former had retained its green colour. Though it revealed little regarding the difficult-to-observe process of digestion of algae, Greenwood noted, such observations were 'valuable inasmuch as when the digestive vacuole is gone, colour and contour mark them out from the surrounding endosarc [i.e. bodily matter] of the Amoeba, and therefore help to supply some links in the chain of change from ingestion to ejection.' The greenness of the Protococcus meant that its movement through the amoeba could be observed with ease compared to less colourful ingesta. Brightly-tinted material presented her amoeboid actors with props, through the following of which Greenwood might narrate the processes of unicellular digestion.'
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Quoted byT. Quick, Minute Mediation: Cell Physiology, Print-Making and Industry in Late Victorian Cambridge
Description:'Greenwood’s earliest articles describe her concern with amoeboid digestion as arising out of the by-then well-known observation that a ‘characteristic’ feature of Rhizopoda was their ‘constant’ ingestion of matter.[1] Whilst many authors had noted the fact that amoeba appeared to ingest material from their surroundings, the processes by which they assimilated material had remained at the margins of histological discourse...
Noting the existence of ‘but few descriptions which deal at all fully with the mode of ingestion, and fewer which give in detail the changes taking place in ingested bodies’, Greenwood implicitly aligned herself with the founding figures of histology.[2] Her commitment to the investigation of cellular activity would lead her away from some of the more contentious theoretical questions that animated histological discourse at this time, such as those arising out of discussions of protoplasm (on which see below), and towards the a then-emerging conception of amoebae not as inert bodies or substance-producing factories, but as animals species in their own right – as species that could be distinguished by their district habits and behaviours as well as by their fixed anatomical states.'
'Greenwood's principal interest in her amoeboid actors did not concern the relationships that they had to one another, but rather the conditions under which they assimilated in order to continue their existence. Central to this concern was consideration of the means by which they incorporated matter from their surroundings. As she noted, though a range of scattered observations existed on the ingestion of outside matter by very simple organisms (most of which took their cue from Ehrenberg's famous contentions regarding the presence of 'stomachs' in 'polgastric infusoria'), there had been no systematic study of the processes of amoeboid digestion.[3]'
'Whereas histological anatomists 'fixed' cells to their slides as a prelude to colouring them with stains, thereby killing them in the process, Greenwood would encourage her objects of study to assimilate coloured matter whilst they were still alive. She portrayed this strategy as having emerged during a chance observation, during which an amoeba formed a vacuole around 'a Monad... and a green Protococcus' (a type of algae, coloured green by chlorophyll). Over a period of six hours, Greenwood had watched the incorporation of the Protococcus into the body of the amoeba, at the end of which the former had retained its green colour. Though it revealed little regarding the difficult-to-observe process of digestion of algae, Greenwood noted, such observations were 'valuable inasmuch as when the digestive vacuole is gone, colour and contour mark them out from the surrounding endosarc [i.e. bodily matter] of the Amoeba, and therefore help to supply some links in the chain of change from ingestion to ejection.'[4] The greenness of the Protococcus meant that its movement through the amoeba could be observed with ease compared to less colourful ingesta. Brightly-tinted material presented her amoeboid actors with props, through the following of which Greenwood might narrate the processes of unicellular digestion.'
[1] Greenwood, 1886.
[2] Greenwood Rhizopods 1886, p. 258.
[3] Greenwood, 1886, pp.
[4] Greenwood, 1886, pp. 262-263.
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