XVI. On the action of heat upon the contagium in the two forms of Septichsemia known respectively as ‘ Davaine’s ’ and ‘ Pasteur’s

1883 ◽  
Vol 34 (220-223) ◽  
pp. 150-156
Keyword(s):  
Guinea Pig ◽  
Subcutaneous Tissue ◽  
Monday Morning ◽  
Advanced Stage ◽  
Serous Fluid ◽  
Rapid Decomposition ◽  
Acute Peritonitis ◽  
The Subject ◽  
Destructive Inflammation ◽  
Micro Organisms

Professor Rosenberger, of Würzburg, has recently published the results of experiments, by which he claims to have effectually sterilised by heat, the blood and exudation fluids of the rabbit in the two forms of septichæmia, known as those of Davaine and Pasteur; and he states that these fluids so sterilised, upon injection into other animals, were found to be infective, reproducing the disease with the recurrence of the specific organisms which characterise it: he therefore regards these organisms as having no causal connexion with the affections in which they are found, but as merely secondary or epiphenomenal. That this would be the necessary deduction from the experiments mentioned, if it were proved that the fluids had been effectively sterilised, is obvious; but the account published contains no details whatever of the methods employed, nor protocol of the experiments, so that it is impossible either to discuss them or to form a judgment as to the correctness of the conclusions. They, however, involve a question so important in respect to the theory of contagium vivum—the relations of these micro-organisms to disease—that it was determined to work out the subject on the basis indicated in Professor Rosenberger’s paper, adopting such methods and precautions as appeared necessary. Guinea-pig No. 1.—0·7 cub. centim. of putrid ox-blood was injected with a Pravart’s syringe, into the peritoneal cavity of a full-grown guinea-pig, which the next morning was found recently dead, rigor not having set in: round the place of injection there was some subcutaneous exudation, with destructive inflammation of the tissues of the abdominal wall, sections of which showed numerous Bacilli and Micrococci in the layers of connective tissue between the museles. Acute peritonitis was found with a large exudation of serous fluid containing some extravasated blood-corpuscles, and deeply stained with their colouring matter. The fluid in this case was not very coagulable, differing in this respect from some others. The same day 0·5 cub. centim. of the peritoneal exudation fluid of No. 1 was injected into the subcutaneous tissue of the abdomen of guinea-pig No. 2, which, as the following day was Sunday, was not examined till Monday morning, when it was found dead, and in a much more advanced stage of decomposition than would have occurred normally in the same period. In all forms of septichæmia this rapid decomposition is invariably found. Guinea-pig No. 3 then received in similar manner 0·5 cub. centim. of the diluted subcutaneous exudation fluid of No. 2, which, likewise, was not coagulated.

scholarly journals EPIDEMIC ENCEPHALITIS AND SIMPLE HERPES

1927 ◽  
Vol 8 (6) ◽  
pp. 713-726 ◽  
Author(s):  
Simon Flexner
Keyword(s):  
Guinea Pig ◽  
Past Experience ◽  
The State ◽  
Encephalitis Virus ◽  
Point Of View ◽  
Epidemic Encephalitis ◽  
Direct Corollary ◽  
The Subject ◽  
Positive Results ◽  
Epidemic Diseases

The purpose of this paper is to explain the state of our knowledge of the etiology of epidemic encephalitis, and especially to draw a line of demarcation between the established virus of simple herpes and the hypothetical virus of epidemic encephalitis. It had already been shown that the experimental observations on rabbits do no suffice to prove the identity of the herpes with the encephalitis virus. The discussion of the subject in this paper shows that identity cannot be postulated on the basis of the performed guinea pig experiments. Attention has been drawn to the significant fact that there is lack of harmony in the positive results of those investigators who believe that the incitants of epidemic encephalitis have been discovered. An attempt has been made to attribute some of the discrepancies reported by these investigators either to accidental and contaminating microbic agents, or to the uncovering of virulent agents preexisting in a latent state in the animals employed for inoculation, the existence of which was not previously known or suspected. Since past experience leads us to believe in a single incitant for widespread epidemic diseases, it is probable that, when certainly discovered, the microbe of epidemic encephalitis will prove to be simple and not multiple. The direct corollary to this point of view is that up to the present, the etiology of epidemic encephalitis has not been determined.

Perfusion rates and the transfer of water across isolated guinea pig placenta

1977 ◽  
Vol 232 (6) ◽  
pp. H666-H670
Author(s):  
H. Schroder ◽  
H. P. Leichtweiss
Keyword(s):  
Guinea Pig ◽  
Flow System ◽  
Tritiated Water ◽  
Countercurrent Flow ◽  
Concurrent System ◽  
Flow Rates ◽  
Guinea Pig Placenta ◽  
The Subject ◽  
Pig Placenta ◽  
Relative Transfer

The transfer of tritiated water across the isolated, artificially perfused guinea pig placenta was the subject of 21 experiments. The observed relationship between the flow rates and the relative transfer of water cannot be explained by a concurrent or pool-flow system. If the direction of the fetal flow is reversed, the rate of transfer is lowered. It may be concluded, that the decrease is a result of a change from a nonideal countercurrent flow system to a nonideal concurrent system. This conclusion, however, holds only if all other parameters that determine the exchange as well remain unaffected. In the range of flows investigated, the transfer of water is flow limited.

scholarly journals Digestion of grass lipids and pigments in the sheep rumen

1974 ◽  
Vol 32 (2) ◽  
pp. 327-340 ◽  
Author(s):  
R. M. C. Dawson ◽  
Norma Hemington
Keyword(s):  
Small Proportion ◽  
Polar Compounds ◽  
The Other ◽  
Chlorophyll Pigments ◽  
Rapid Decomposition ◽  
Other Hand ◽  
Sheep Rumen ◽  
Micro Organisms

1. Digestion of grass lipids and pigments in the rumen of the sheep has been studied during starvation and following the administration of 14C-labelled grass.2. Both galactolipids contained in chloroplasts are rapidly degraded, although mono-galactosyldiglycerides disappear faster than digalactosyldiglycerides. It was concluded that rumen micro-organisms are mainly responsible for this degradation, although grass itself also contains enzymes which can degrade galactolipids.3. Rumen contents can degrade added 14C-labelled mono- and digalactosyldiglycerides in vitro at a rate sufficient to account for the disappearance of galactolipids in the intact rumen. The initial enzyme attack is probably a successive deacylation to give monogalactosylglycerol and digalactosylglycerol.4. Most of the chlorophyll pigments are rapidly converted into phaeophytins by loss of magnesium. A small proportion of chlorophyll a and more of chlorophyll b remains intact even after 24 h starvation. On the other hand, about half the phaeophytin undergoes further rapid decomposition to yield phylloerythrin.5. Although the grass phospholipids are extensively degraded, β-carotenes and many non-polar compounds, e.g. steroids, appear to undergo little change in the rumen.

scholarly journals Preface - The British contribution to the SCOPE Programme on the Ecology of Biological Invasions

1986 ◽  
Vol 314 (1167) ◽  
pp. 503-504 ◽  
Keyword(s):  
Biological Invasions ◽  
National Parks ◽  
Mediterranean Climate ◽  
Natural Ecosystems ◽  
Native Forests ◽  
Natural Extensions ◽  
Biogeographical Regions ◽  
The Subject ◽  
Micro Organisms ◽  
The Impact

SCOPE, the Scientific Committee on Problems of the Environment, analyses such problems by means of programmes leading to published reports on the state of knowledge. The meeting reported here was the major British contribution to the SCOPE Programme on the Ecology of Biological Invasions. It is a slightly unusual programme for SCOPE in that the subject is an entirely biological one, and also in that, although most of the problems are caused by invasions induced by man, some can arise as a result of natural extensions of range. Such effects are often acute in ecosystems with a mediterranean climate away from the Mediterranean itself, that is to say in California, South Africa and Australia. These mediterranean zones are in different biogeographical regions, so the organisms native and introduced to them have, in general, no evolutionary experience of each other. Species introduced from one such region to another have frequently spread in semi-natural and natural ecosystems. The SCOPE programme arises from concern about the impact and management of such pests in particular. The preamble to the programme (Anon. 1985) therefore talks about ‘ the introduction of plants, animals and micro-organisms to regions remote from their centres of origin. ’ It goes on to say that the ‘ areas include a wide variety of non-agricultural, non-urban land such as native forests and rangelands, and protected areas like National Parks and Ecological Reserves.’

Leeuwenhoek Lecture: Soil metabolism

1955 ◽  
Vol 143 (911) ◽  
pp. 159-178 ◽  
Keyword(s):  
Dynamic Equilibrium ◽  
Soil Microbiology ◽  
Ion Concentration ◽  
Complex Biological System ◽  
Hydrogen Ion Concentration ◽  
Aeration Conditions ◽  
The Subject ◽  
Micro Organisms ◽  
Physical And Chemical ◽  
Soil Metabolism

It is a signal honour to be invited to give the Leeuwenhoek Lecture, and I would like to thank the authorities of the Royal Society for their invitation to me to give this lecture on the chemical aspects of soil microbiology. Leeuwenhoek clearly perceived from his pioneer work that a vast world of micro-organisms lies in the soil. The importance of its study, both in the purely scientific domain and in the practical fields of agriculture and medicine, is only now being realized. I will try in this lecture to give a short description of some recent studies of the chemical aspects of soil microbiology with a few observations on their practical implications. Some conception of the enormous population of micro-organisms in soil is provided by the fact that there may be as many as 5000 million bacteria per gram of soil. This corresponds to a weight of over 4 tons of bacterial substance per acre of soil. The numbers of bacteria fluctuate very greatly depending on availability of food supply, moisture, aeration conditions, temperature, hydrogen-ion concentration of the soil, and other factors. Protozoa may reach figures of the order of 1 million per gram of soil and algae may exceed a hundred thousand per gram. Actinomycetes and fungi, the exact numbers of which are difficult to estimate, may have a combined weight in the soil equal to that of the bacteria. Kluyver (1953) makes a comment in his recent Leeuwenhoek Lecture that the weight of microbial protoplasm on earth surpasses that of animal protoplasm by almost twenty times. It is obvious, therefore, that in dealing with the subject of soil metabolism we are dealing with the metabolism of vast numbers of living cells, greatly exceeding the number of cells found in animal life. The organisms of soil do not develop in an unrestricted chaotic manner. They are, on the other hand, greatly dependent on each other, sharing many factors in common. Soil may be considered to be a complex biological system in which hosts of organisms compete with each other often for a limited supply of nutritional material. They exercise profound effects on each others’ development and chemical activities, and they establish between themselves a dynamic equilibrium which continually changes with the changes in the physical and chemical environment of the soil.

scholarly journals An experimental enquiry into the nature of the substance in serum which influences phagocytosis

1905 ◽  
Vol 76 (512) ◽  
pp. 506-524 ◽  
Keyword(s):  
Immune Serum ◽  
Normal Serum ◽  
Bacterial Invasion ◽  
Susceptible Animal ◽  
Destructive Action ◽  
The Face ◽  
The Subject ◽  
Micro Organisms ◽  
To Receive ◽  
Highly Virulent

Metchnikoff, and his school, in the face of much opposition, lasting many years, have offered convincing proofs of the importance of phagocytosis in the protection of the animal body against bacterial invasion. The main theses of the Metchnikovian theory are now almost universally accepted, but the exact mechanism of the processes involved is even now the subject of keen controversy. If a highly virulent organism is injected into a susceptible animal, the leucocytes appear to be repelled, and to be unable to deal with the microbe, which multiplies and causes the death of the animal. If, however, the suitable immune serum is injected into the animal before inoculation, the phagocytes attack and devour the invading micro-organisms. Much discussion has centred round the interpretation of such experiments. The early work of Nuttall and others on the bactericidal action of normal serum, and Pfeiffer’s demonstration of the bacteriolysis of cholera and typhoid bacilli by immune sera in the absence of cells, formed the chief basis on which rested the humoral theory, which attributed the protection in such cases to the destructive action of the serum on the microbes. Flügge graphically illustrated the view of the humoralists by likening the phagocytes to the trenches made ready behind the fighting line to receive the conquered dead.

scholarly journals FURTHER STUDIES ON THE ETIOLOGICAL RÔLE OF VIBRIO FETUS

1920 ◽  
Vol 32 (6) ◽  
pp. 683-689 ◽  
Author(s):  
Theobald Smith ◽  
Ralph B. Little ◽  
Marian S. Taylor
Keyword(s):  
Guinea Pig ◽  
Blood Serum ◽  
Placental Tissue ◽  
Infectious Agent ◽  
The Other ◽  
Advanced Stage ◽  
Young Stock ◽  
Tentative Hypothesis ◽  
Agglutination Titer ◽  
Rule Out

The data bearing on these three cases are quite sufficient to rule out Bacillus abortus as the agent. Not only the cultures and guinea pig tests of fetal tissues and contents of the digestive tract, but also the agglutination and guinea pig tests of the milk, were negative. The same is true of the agglutination tests of the blood serum. Only in one case was the placenta obtained in part. The stained films and the sections from various regions showed no abortion bacilli. Guinea pig tests of placental tissue were negative for Bacillus abortus. On the other hand) minute organisms resembling vibrios were detected in the cytoplasm of endothelial cells within capillaries in the edematous subchorionic tissue. Subsequently the agglutination titer of the blood serum of one of these cases rose to a level indicating infection with Bacillus abortus during the second pregnancy. The peculiar distribution of abortions due to Vibrio fetus among older cows and heifers in this herd, resulting at first in cases among older cows and latterly passing to young stock, may be explained by certain occurrences in the herd itself. It may be assumed that the infection was originally brought in by purchased cows. The young stock is kept segregated from these in a special barn, and when 6 months old it is pastured on outlying farms until returned in an advanced stage of pregnancy. The heifers during the first pregnancy were thus kept away from vibrio carriers until after the first calf was born. In June and July, 1919, 55 older cows, purchased and native, were placed on the young stock pasture. The three cases of abortion in heifers due to Vibrio fetus occurred October 24, November 9, and December 2, 1919. The age and condition of the fetuses accord very well with the assumption that Vibrio fetus was introduced among the young stock in June or July of the same year. The information gathered thus far concerning vibrionic abortion in this herd enables us to formulate a tentative hypothesis subject to modification with increasing knowledge of this type of infectious abortion. The infectious agent was probably introduced by purchased cows in 1917 or earlier. It gained a certain headway up to 1919, then the number of cases declined so that between May, 1919, and May, 1920, only the above three cases in heifers, and one case of mixed infection with Bacillus abortus in an older cow, were detected. During the same period cases due to Bacillus abortus continued undiminished. The greater resistance of Bacillus abortus manifested in cultures as compared with Vibrio fetus is thus reflected in its behavior in nature. The temporary dying out of the infection indicates that natural immunization of a herd to Vibrio fetus proceeds quite rapidly. Another outbreak may be expected when the immunity of the herd has declined in the absence of the infecting agent and the latter is reintroduced from without, or it may reappear at any time when a vibrio of higher virulence is brought in.

Base Metal Tank Bioleaching: From Laboratory Test Work to Commercialization

2015 ◽  
Vol 1130 ◽  
pp. 197-200 ◽  
Author(s):  
Mariekie Gericke
Keyword(s):  
Laboratory Test ◽  
Base Metal ◽  
Commercial Application ◽  
Commercial Success ◽  
The Past ◽  
Refractory Gold ◽  
Research Programmes ◽  
Scale Test ◽  
The Subject ◽  
Micro Organisms

The tank bioleaching of metal sulphides is an established technology. Commercial success started with the treatment of refractory gold concentrates using mesophilic micro-organisms, followed by the development of tank bioleaching processes for the treatment of base metal concentrates. This was initially a mesophilic process treating secondary copper sulphides, pentlandite and cobaltiferous pyrite. There was though limited potential for recovery of copper from chalcopyrite concentrates due to low copper extractions. Over the past decades the optimization of bioleaching processes for the treatment of chalcopyrite ores and concentrates has been the subject of numerous research programmes. The use of bioleaching for the treatment of pure chalcopyrite concentrates has, however, not found commercial application mainly due to competitive smelter prices. With this in mind, Mintek’s base metal bioleaching development over the past few years focused on the treatment of complex polymetallic concentrates containing contaminants such as As, Bi, Pb and Sb as a niche application for tank bioleaching processes. These contaminants pose problems when processed via the smelting route. This paper reviews Mintek’s involvement in the development of base metal tank bioleaching processes for the treatment of chalcopyrite and polymetallic concentrates. Examples of laboratory-scale test work as well as larger scale demonstration and commercialization of the technology are highlighted.

scholarly journals The Ticks of Rodents and their Nests, and the Discovery that Rhipicephalus sanguineus Latr. is the Vector of Tropical Typhus in Kenya

1935 ◽  
Vol 35 (1) ◽  
pp. 1-22 ◽  
Author(s):  
J. Isgaer Roberts
Keyword(s):  
Guinea Pig ◽  
Positive Result ◽  
Guinea Pigs ◽  
Rhipicephalus Sanguineus ◽  
Weather Conditions ◽  
Human Beings ◽  
Negative Results ◽  
Unfavourable Weather ◽  
The Subject ◽  
Made In

1. Earlier attempts to trace the vector of tropical typhus in Kenya failed. The only references to the subject in the available literature consist of mere suggestions that a mite would most likely prove to be the transmitter.2. An investigation made in an area whence most Nairobi cases of tropical typhus were reported, suggested that a tick (R. pulchellus) would be the most likely vector.3. Transmission experiments made in the belief that one of the unclassed fevers of man was conveyed by R. pulchellus have so far yielded negative results. There is, however, sufficient circumstantial evidence available pointing to this tick as vector of a form of mild typhus to man—this demands further investigation.4. At Mombasa and Nairobi, houses reported to be heavily infested with ticks, or houses investigated after the occurrence of the tropical typhus in them, have yielded only R. sanguineus.5. R. sanguineus (3 ♀), taken from a dog in a house where the last typhus case had occurred 8 months previously, gave a typical typhus syndrome when emulsified and inoculated into a male guinea-pig. R. sanguineus (1 ♀, 12 ⊙), taken in a house where a child had recently contracted typhus, also gave a positive result with guinea-pigs and the virus was further transmitted by passage through other guinea-pigs.6. The infestation of houses by R. sanguineus and the incidence of tropical typhus among human beings appear to be influenced by unfavourable weather conditions, causing the ticks to seek relatively dry and warm places for purposes of oviposition or metamorphosis, thus invading houses. In the absence of dogs, its usual hosts, the tick attacks man.

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