The growth and sporulation of the benign and malignant tertian malarial parasites in the culture tube and in the human host / by John Gordon Thomson and David Thomson.

  • Thomson, J. G. (John Gordon), 1878-1937.
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: The growth and sporulation of the benign and malignant tertian malarial parasites in the culture tube and in the human host / by John Gordon Thomson and David Thomson. Source: Wellcome Collection.

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    pail The blood is defibrinated by gently stirring with the thick wire. Defibrination should be complete in about 5 minutes. The wire with the clot is then removed and the blood is poured into several smaller sterile tubes (about one inch column of blood in each). A rubber cap is placed over the cotton plugs to prevent evaporation and the tubes are then transferred (standing upright) to an incubator at a temperature of 37° to 41°C. The corpuscles settle in a short time, leaving about one half-inch of clear serum at the top. It is apparently unnecessary to remove the leucocytes by centrifugalisation. FURTHER OBSERVATIONS ON CULTIVATION We have grown four complete generations of parasites in one tube by the above method, and we do not see why their growth should not continue indefinitely, provided fresh serum and corpuscles be added. It is not the presence of leucocytes which prevents further development. This is due to degenerative changes taking place in the corpuscles and serum. If the serum and corpuscles be kept in a sterile condition in an ice chest they remain unchanged for a long time; but at the temperature required for the growth of the parasites visible changes take place in a few days. The corpuscles become fragmented and form a brownish débris, and the serum becomes dark brown in colour. When this occurs the parasites are unable to continue their developmental cycle. Bass and Johns in their original paper (1912) stated that the parasites grow only on the surface layer of corpuscles, and that no growth took place in the deeper layers. hey also stated that the serum destroyed the parasites when they escaped from the corpuscles, so that when the spores escape they must enter immediately into a contiguous corpuscle in order to survive. The blood also, in their opinion, required to be heated to a temperature of 40°C. to destroy the complement in the serum; furthermore, in order to cultivate several generations, the leucocytes had to be removed. We do not believe that they have sufficient evidence for these deductions. We find that the parasites develop even in the very deepest layer of the column of corpuscles. Also, it seems rather a contradiction that the parasites should grow best on the surface layer of corpuscles
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