The Two-Cent Solution

SummaryFollowing successful small-scale trials, an attempt was made, by aircraft application of insecticide, to eradicate Glossina morsitans Westw. and G. pallidipes Aust. from an isolated block of savannah woodland, approximately 11 sq. miles in extent, at Chungai in the Central Province of Tanganyika between July 1958 and January 1959. A single-engined aircraft, fitted with two belt-driven rotary-cage atomisers, was used to apply a 5 per cent, solution of γ BHC in power kerosene at a nominal dosage of 0·08 gal. per acre (0.04 lb. γ BHC per acre). Seven applications were made at approximately 28-day intervals, the time taken to complete an application varying from five to eight days. The operation failed to control the flies. Although each of the first two applications reduced the apparent density of G. morsitans by about 90 per cent, and that of G. pallidipes by a lesser, although still considerable, factor, later applications gave varying and often low mortalities, and the populations increased slowly for some time, the insecticide applications causing only temporary depressions in numbers. Numbers fell towards the end of the operation, but final reductions were only about 50 per cent, or less. Kills of female flies were low, and this undoubtedly led to the eventual failure.The low volume-dosage, a drop spectrum that possibly contained too few droplets of the required size, meteorological conditions, and biological factors that apparently favoured the survival of female flies are suggested as contributory elements to the low mortalities.Operational costs were considerably lower than in previous work.

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Professor Betz's Method of Making Sections of Nervous Tissue

Journal of Mental Science ◽

10.1192/bjp.19.87.465 ◽

1873 ◽

Vol 19 (87) ◽

pp. 465-466

Author(s):

Batty Tuke

Keyword(s):

Spinal Cord ◽

Dura Mater ◽

Nervous Tissue ◽

Cool Temperature ◽

Cent Solution ◽

Pia Mater ◽

Thin Sections ◽

Brown Colour ◽

Ordinary Temperature

Professor Betz, of Kiew, has lately produced brain sections, which have attracted very considerable attention in Vienna. His specimens are of vast extent. He appears to be able to produce thin sections of an entire hemisphere. We append his method of hardening and cutting as it is stated in the “Correspondentze Blatt der deutschen Gesellschaft für Psychiatrie und Gerichtlich Psychologie, Jan., 1873.” The method of hardening which we wish to bring into notice is as follows:—observing that differences exist in the treatment of the spinal-cord, cerebrum and cerebellum. The spinal-cord—after tbe careful removal of the dura mater, it is placed in spirit of from 75 to 80 per cent., which is tinged a clear brown colour by the addition of Iodine. After from one to three days, during which the preparation must stand in a cool temperature, the Pia Mater and the Arachnoid are also removed; the specimen remaining in the spirit, to which a few drops of Iodine must be added daily for three days, maintaining an ordinary temperature. It is then transferred to a three per cent. solution of Chromate of Potass, and back again to the cool temperature. Here it hardens thoroughly, which is known by the fluid becoming turbid, and by the formation of a brown deposit upon the preparation. When this occurs, it must be immediately thoroughly washed with water, and immersed in a solution of Chromate of Potass, from a half to one per cent. strength, in which it will not become too hard or brittle.

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THE REMOVAL OF AGGLUTININ FROM SENSITIZED MOTILE BACTERIA

Journal of Experimental Medicine ◽

10.1084/jem.48.6.825 ◽

1928 ◽

Vol 48 (6) ◽

pp. 825-836

Author(s):

John B. Nelson

Keyword(s):

Cent Solution ◽

No Removal ◽

Motile Bacteria

It was shown that flocculating (flagellar) agglutinin and granulating (somatic) agglutinin display certain differences with respect to their removal from sensitized bacteria (B. paratyphi). A 5 per cent solution of NaCl added to sedimented, sensitized bacteria followed by heating to 60°C. for 1 hour removed approximately 50 per cent of the combined agglutinin. There was little or no removal of granulating agglutinin either from the sensitized motile bacteria or from a sensitized non-motile organism (Staphylococcus). Evidence was presented that the agglutinin removal was not dependent solely on disintegration of flagella by the conditions of extraction with a subsequent freeing of antibody.

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A new method for the determination of ammoniacal nitrogen in soils

The Journal of Agricultural Science ◽

10.1017/s002185960000397x ◽

1924 ◽

Vol 14 (4) ◽

pp. 548-554 ◽

Cited By ~ 10

Author(s):

W. McLean ◽

G. W. Robinson

Keyword(s):

Sodium Chloride ◽

New Method ◽

Ammoniacal Nitrogen ◽

Cent Solution ◽

Base Exchange ◽

Exchangeable Bases ◽

Cent Sodium ◽

Leaching Solution ◽

Ammonium Compounds

A method for the determination of ammoniacal nitrogen in soils is described. It is an extension of the Hissink method for exchangeable bases to ammonium present in the soil. The working details are similar to the Hissink method, except that the leaching process is entirely carried out in the cold. The ammonia is distilled off with magnesium oxide.Using normal sodium chloride as a leaching solution and collecting half a litre of leachings for distillation with magnesia, results were obtained which showed excellent agreement with those by the aeration method. Similar results were obtained using 250 c.c. of 15 per cent, sodium chloride solution, but the results are on an average about 1·6 per cent, lower. With high proportions of ammoniacal nitrogen a second half litre of normal sodium chloride leachings should be taken, or half a litre of 15 per cent, solution used.The leaching method is economical of apparatus and water supply. It is therefore suitable for small laboratories with limited resources. It is fairly rapid: six estimations can be completed in a day.The close agreement of the new method with the aeration method suggests that the amount of ammoniacal nitrogen in the soil at any given time is not an arbitrary quantity depending on conditions of estimation, but a definite amount. It is improbable that any ammonium compounds exist in the soil apart from those which take part in base exchange.

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INFLUENCE OF THE CONCENTRATION OF ELECTROLYTES ON SOME PHYSICAL PROPERTIES OF COLLOIDS AND OF CRYSTALLOIDS

The Journal of General Physiology ◽

10.1085/jgp.2.3.273 ◽

1920 ◽

Vol 2 (3) ◽

pp. 273-296 ◽

Cited By ~ 4

Author(s):

Jacques Loeb

Keyword(s):

Physical Properties ◽

Osmotic Pressure ◽

Initial Rate ◽

Charged Particles ◽

Distilled Water ◽

Neutral Salt ◽

Gelatin Solution ◽

Acid Salt ◽

Cent Solution ◽

Depressing Effect

1. When a 1 per cent solution of a metal gelatinate, e.g. Na gelatinate, of pH = 8.4 is separated from distilled water by a collodion membrane, water will diffuse into the solution with a certain rate which can be measured by the rise of the level of the liquid in a manometer. When to such a solution alkali or neutral salt is added the initial rate with which water will diffuse into the solution is diminished and the more so the more alkali or salt is added. This depressing effect of the addition of alkali and neutral salt is greater when the cation of the electrolyte added is bivalent than when it is monovalent. This seems to indicate that the depressing effect is due to the cation of the electrolyte added. 2. When a neutral M/256 solution of a salt with monovalent cation (e.g. Na2SO4 or K4Fe(CN)6, etc.) is separated from distilled water by a collodion membrane, water will diffuse into the solution with a certain initial rate. When to such a solution alkali or neutral salt is added, the initial rate with which water will diffuse into the solution is diminished and the more so the more alkali or salt is added. The depressing effect of the addition of alkali or neutral salt is greater when the cation of the electrolyte added is bivalent than when it is monovalent. This seems to indicate that the depressing effect is due to the cation of the electrolyte added. The membranes used in these experiments were not treated with gelatin. 3. It can be shown that water diffuses through the collodion membrane in the form of positively charged particles under the conditions mentioned in (1) and (2). In the case of diffusion of water into a neutral solution of a salt with monovalent or bivalent cation the effect of the addition of electrolyte on the rate of diffusion can be explained on the basis of the influence of the ions on the electrification and the rate of diffusion of electrified particles of water. Since the influence of the addition of electrolyte seems to be the same in the case of solutions of metal gelatinate, the question arises whether this influence of the addition of electrolyte cannot also be explained in the same way, and, if this be true, the further question can be raised whether this depressing effect necessarily depends upon the colloidal character of the gelatin solution, or whether we are not dealing in both cases with the same property of matter; namely, the influence of ions on the electrification and rate of diffusion of water through a membrane. 4. It can be shown that the curve representing the influence of the concentration of electrolyte on the initial rate of diffusion of water from solvent into the solution through the membrane is similar to the curve representing the permanent osmotic pressure of the gelatin solution. The question which has been raised in (3) should then apply also to the influence of the concentration of ions upon the osmotic pressure and perhaps other physical properties of gelatin which depend in a similar way upon the concentration of electrolyte added; e.g., swelling. 5. When a 1 per cent solution of a gelatin-acid salt, e.g. gelatin chloride, of pH 3.4 is separated from distilled water by a collodion membrane, water will diffuse into the solution with a certain rate. When to such a solution acid or neutral salt is added—taking care in the latter case that the pH is not altered—the initial rate with which water will diffuse into the solution is diminished and the more so the more acid or salt is added. Water diffuses into a gelatin chloride solution through a collodion membrane in the form of negatively charged particles. 6. When we replace the gelatin-acid salt by a crystalloidal salt, which causes the water to diffuse through the collodion membrane in the form of negatively charged particles, e.g. M/512 Al2Cl6, we find that the addition of acid or of neutral salt will diminish the initial rate with which water diffuses into the M/512 solution of Al2Cl6, in a similar way as it does in the case of a solution of a gelatin-acid salt.

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THE ACTIVATION OF PROTHROMBIN, WITH SPECIAL REFERENCE TO "THROMBOPLASTIC ENZYME" (TRYPTASE)

Blood ◽

10.1182/blood.v3.10.1130.1130 ◽

1948 ◽

Vol 3 (10) ◽

pp. 1130-1160 ◽

Cited By ~ 7

Author(s):

JOHN H. FERGUSON ◽

BURTON L. TRAVIS ◽

EARL B. GERHEIM

Keyword(s):

Activation Process ◽

Cent Solution ◽

High Potency ◽

Trace Impurities ◽

Accessory Factor ◽

Ca Ions ◽

Special Circumstances ◽

Tissue Origin ◽

Rate Of Activation ◽

Thrombin Formation

Abstract A number of high-potency purified prothrombin preparations,61 in 0.2-0.5 per cent solution in borate buffer (pH = 7.7), maintain for days or weeks a stable thrombin-forming ability, whether (a) with buffer alone, (b) with brain thromboplastin suspension, (c) with CaCl2. Nevertheless, they all contain a trace of thrombin and continue to activate "spontaneously" at a very slow rate. Optimal addition of Ca-salt somewhat accelerates this and usually leads to maximal (complete) thrombin formation in 2-11 days at room temperature. Except in a few cases, where ionized Ca++ is demonstrable, thromboplastin, alone, is without effect, but added with calcium, it completes the activation in a matter of minutes or hours depending principally upon the concentration used. Experimental analysis of the activation process stresses the participation of (1) Ca-ions, (2) thromboplastic P-lipid factor (cephalin), (3) plasma and tissue tryptase (proteolytic enzyme). Each of these factors is studied in detail with reference to mode of action, optimal concentration, side-effects, and relation to inhibitors. Inhibition of prothrombin activation may be considered under the following heads: (1) "decalcifying" agents (e.g., oxalates, citrates, etc.), which (a) depress Ca-ionization and thus prevent thrombin formation, and (b), under special circumstances, reverse the process of activation; (2) "antithromboplastic" (? anticephalin) agents, (e.g., heparin, and probably soybean trypsin-inhibitor, to some extent); (3) "antitryptase" agents (e.g., crystalline trypsin-inhibitors from pancreas and soybean), which inhibit the thromboplastic enzyme (accessory factor). Excess Ca++ slows rate of thrombin formation. The evidence suggests that thrombin formation proceeds via an "intermediary" calcium-prothrombin-cephalin (thromboplastic phosphatide) complex or compound. The amounts of (a) thromboplastic P-lipid (cephalin or "thromboplastin") and (b) Ca++ determine both the rate of activation and the final thrombin yield. However, the ultimate ("ripe") thrombin owes none of its activity to the presence of any calcium or phospholipid. The three types of activator (Ca, thromboplastin, and thromboplastic enzyme) occur as "trace impurities" in prothrombin preparations, but Seegers’ most purified materials are tryptase-free. Tryptase (and trypsin) are "thromboplastic" only in the presence of adequate calcium and phospholipid factors, which may, however, be "mobilized" from protein combination, including prothrombin. In this way the two basic activators are, in a sense, "catalyzed" in their prothrombin-activating reactions. The significance of proteolytic actions (fibrinolysis, fibrinogenolysis, prothrombinolysis, and sometimes thrombinolysis) by natural tryptase of plasma and tissue origin is investigated and discussed in relation to the broader aspects of the blood-coagulation problem.

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The development of rana temporaria under the influence of cane sugar solution

Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character ◽

10.1098/rspb.1933.0015 ◽

1933 ◽

Vol 112 (777) ◽

pp. 359-365 ◽

Cited By ~ 5

Keyword(s):

Rana Temporaria ◽

Cane Sugar ◽

Common Salt ◽

Sugar Solution ◽

Cent Solution ◽

Foul Water ◽

Further Development

The main object of the investigations, the results of which are embodied in this paper, was to repeat certain experiments performed by Tornier (1908) and to confirm or confute his conclusions. Tornier experimented with the eggs of Amphibia— Rana, Bufo and in particular the Axolotl ( Amblystoma ), keeping them for 48 hours in an 8 per cent. solution of cane sugar, then transferring them for 24 hours to a 2 per cent. Solution, and after that to well aerated water in which they completed their development. As a result of this treatment, in further development all sorts of abnormalities, turned up, such as short bodies, swollen abdomens, enlarged mouth cavities, etc. Since similar abnormalities were produced by the use of solutions of glycerine and common salt, Tornier concluded that the energy of the germinal part of the egg had been affected by the reagents used, and that what he termed “plasma-weakness” had been produced, so that the yolky part of the egg, being no longer controlled, swelled up and crushed the more protoplasmic part. He thought that the weakness was immediately due to the cutting off of oxygen by the reagent. He considered that the results which he had obtained with Amphibian eggs explained the production of the “fancy” races of goldfish, because the Chinese breeders, with whom these races originated, were accustomed to rear the spawn of their fish in foul water.

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