The toxicology of plants in South Africa

No abstract available.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The detection of strychnine in carcasses and corpses

(1) In order to express a definite opinion as to the presence or absence of strychnine in purified extracts of specimens of organs, etc., it is essential that the following tests be conducted: (a) taste test, (b) colour test, and (c) a biological test. Immature white mice are for various reasons more suited to the biological test than frogs, (Rana esculenta, Rana pipiens, Rana palustris, Rana aqualensis). It is definite that very unreliable and inaccurate results will be obtained if both the colour and biological tests for strychnine are not applied to extracts as a large number of chemical substances, including ptomaines, are known which yield positive results either with the colour test, or with the biological test for strychnine. Many of these substances also have a bitter taste. The greatest care should be exercised in expressing an opinion as to the presence of strychnine in decomposed carcasses and corpses. The author isolated a strychnine-like ptomaine(s) from a decomposed liver, which was known not to contain any strychnine. This ptomaine(s) had a bitter taste and gave a positive sulphuric acid-potassium bichromate test for strychnine. The results of taste, chemical and biological tests with unidentified and identified ptomaines are recorded. (2) If three weeks old white mice are used in the biological test at least 0.008 mgm. strychnine sulphate is required in order to produce recognisable strychnine spasms in a mouse weighing 10 to 12 gm. With 14 day old white mice weighing 5 to 6 gm. 0.004 mgm. strychnine sulphate is detectable. In order to achieve reliable results in the detection of strychnine in purified extracts of organs, etc., at least 0.011 mgm. strychnine sulphate should be present as approximately 0.007 mgm. is required for the Otto test and 0.004 mgm. For the biological test if this is conducted upon 14-day old white mice weighing from 5 to 6 gm. If three-weeks-old white mice are employed the least amount of strychnine detectable in extracts is 0.015 mgm. if both the Otto and biological tests are conducted. (3) The symptoms of strychnine poisoning in white mice and in the frog (Rana aqualensis) are described. (4) The taste test and chemical and biological tests for strychnine are discussed. (5) Factors responsible for the disappearance of strychnine from corpses and carcasses are discussed. Of four dogs killed with strychnine and exhumed ten weeks after death strychnine was detectable in three carcasses, whilst of four carcasses exhumed eighteen weeks after death only one was positive for strychnine. Eleven months after death eight carcasses of dogs killed with strychnine were exhumed and strychnine was detectable in only four of these. Subsequent exhumations of carcasses of dogs killed with strychnine and of control dogs are to be conducted. (6) Methods of extracting strychnine from carcasses and corpses and of purifying these extracts are discussed. (7) In fresh carcasses and corpses the most suitable organs for analysis for the presence of strychnine are liver, stomach, spleen, lung and the central nervous system; also the urine. (8) In two out of three dogs, which had received strychnine as a tonic, strychnine was detectable in the liver and stomach (plus contents). (9) A large number of chemical substances, which resemble strychnine chemically and biologically, are discussed.The articles have been scanned in colour with a HP Scanjet 5590;300dpi. adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Plant poisoning in stock and the development of tolerance

From the results of experiments conducted upon thirty-two rabbits it appears (a) that the continuous ingestion of leaves or underground stems of gifblaar does not induce the development of tolerance to this plant; and (b) that the active principle of gifblaar has cumulative effects, that is, it is inactivated in the body or excreted at a very slow rate. It is also possible that repeated small doses of the plant may cause progressive damage to organs of vital importance (heart) and that the sum total of these consecutive and progressive lesions is sufficient to cause death in spite of the fact that the active principle has been partly or completely excreted. There also was a certain amount of evidence that some animals became sensitized to the effects of the plant, unless we accept that these animals possessed an idiosyncrasy to gifblaar.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn2015mn201

Fungi in relation to health in man and animal

This paper principally concerns poisonous symbiotic and parasitic fungi attacking foodstuffs, and includes those containing the poison within themselves, for example, ergot, and those producing harmful substances in the foodstuffs on which they grow. It commences with a historical survey of records of fungus-infected foodstuffs, followed by a consideration of the toxic constituents of fungi and infected foodstuffs, and immunity to such poisoning, both natural and acquired. Details are then presented, in tabular form, of experiments conducted to determine the harmful effects of fungus-infected foodstuffs. These do not lend themselves to abstraction and the original should be consulted by those interested. According to the author, all fungus-infected foodstuffs should be considered poisonous until extensive feeding experiments have shown the contrary to be the case. Some cases of suspected food poisoning appear to be either botulism or parabotulism. So-called " fresh hay poisoning " is still a mystery. Different animals display marked differences in susceptibility to fungus-infected foodstuffs. Regarding harmful mouldy foodstuffs, it is stated that it could be fed to some animals with impunity, provided that the quantity fed did not exceed 10 per cent. of the total ration. The toxicity of Lolium temulentum (darnel) to man and animals is due to an alkaloid, temulin, present in grain attacked by Endoconidium temulentum. Two rabbits, a pig and a dog fed on fungus-infected darnel suffered no ill effects.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Recent investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa. XVI

Drenching experiments with eight suspected poisonous plants and one specimen of fungus-infected mealie meal were conducted upon rabbits and sheep. The only positive result achieved was with Agave Americana and, even in this case, it cannot be stated definitely that the paralysis developed by the rabbit was caused by this plant, as conclusions drawn from an experiment conducted on a single animal may not be reliable.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Gebruik van proefdiere in biomediese navorsing, met spesiale verwysing na eksperimentele chirurgie

The choice of an experimental-animal model is of great importance since the acquisition and maintenance of experimental animals often constitute the largest cost item in the experiment. More emphasis should therefore be laid on qualitative than on quantitative results. Following the development of improved conventional breeding methods and the development of specifically pathogen-free and germ-free methods, the standard of experimental animals has been raised substantially and more reliable results are being attained with more uniform experimental animals Research scientists are continually searching for new animal models, especially animals that are phylogenetically closely related to man, such as the sub-human primates of which there are at present a good but decreasing supply in South Africa. Domestic animals have long been used as models in the study of Zoonosis and for naturally occurring conditions in humans and animals. Many problems have already been noticed, but others are still awaiting clarification. Experimental surgery has proved its value in fields such as microvascular surgery, intra-uterine surgery, endocrinology, tissue transplantation, as well as other fields. The veterinarian has played an important part in this work. He should be part of a multi disciplinary team, should see to the well-being and health of the animals, should ensure that the ethical and legal aspects of animal research are complied with, should assist in the development of new models, and should serve in a consultative capacity in the planning of animal experiments. A number of suggestions are made. Post-graduate training in experimental- animal science and legislation to control the use of animals in experimental work should be given urgent attention. Co-operation at research level between the Veterinary and Medical Faculties should be promoted. The provision of experimental-animal faculties for the enlarged Faculty of Veterinary Science and the Faculty of Medicine is sure to result in fruitful co-operation.p. 19-22 : Publikasies van die Universiteit van Pretoria (Nuwe Reeks)http://explore.up.ac.za/record=b179663

Recent investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa

The toxicity of fourteen plants were investigated. The symptoms and post mortem appearances caused by three plants, which have previously not been proved poisonous, are described. These three plants are (a) Epaltes alata Steetz. (b) Homeria pura N.E. Br. and (c) Albuca sp. (O.P.H . No. 6726, 3.10.33; N.H.P. No. 15726). According to the results of the experiments conducted no definite opinion as to the toxicity of Zygophyllum foetidum Schrag. can be expressed. An acid environment has no effect on the active principle of gifblaar in the course of twenty-four hours.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn2015mn201

Plant poisoning in stock and the development of tolerance

It is possible to cause the development of tolerance in animals, to certain poisonous plants, by drenching them with small and increasing quantities, whilst others do not produce this phenomenon and may even cause sensitisation, or have cumulative effects. The well known fact that animals, newly introduced to farms infested with poisonous plants, are much more liable to succumb to plant poisoning than animals born and reared on such farms, is most probably partly due to an acquired tolerance developed in the course of time by repeatedly partaking of small quantities of these plants. It is fully realised that discriminate feeding, which is a characteristic of stock reared in areas infested with poisonous plants, plays a very important role in the prevention of plant poisoning in these animals. Theories of tolerance and desensitisation are discussed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Recent investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa

The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The toxicity of sodium chlorate

In New Zealand sodium chlorate is recommended as an efficient destroyer of ragwort, while reports from the United States of America state it to be effective as a general weed-killer. The fact that sodium chlorate is of comparative low toxicity to stock would seem to warrant the conducting of experiments with a view to ascertaining its value as a general weed-killer on South African pastures.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201