ESTIMATION OF THE PURITY OF PREPARATIONS OF ELEMENTARY BODIES OF VACCINIA.
A method of estimating the purity of preparations of elementary bodies of vaccinia is described. It depends on the comparison of the number of infective units of virus in a given material with the number of elementary bodies. The latter figure is estimated from the dry weight of the preparation by means of a calculated value for the weight of a single dehydrated elementary body. Values for the ratio of infective units of vaccine virus to elementary bodies varied between 1 : 2.4 and 1 : 9.2 in seven consecutive experiments; the average was 1:4.2. These ratios indicate a high degree of purity of the preparation. Moreover, they indicate that a relatively high percentage of the elementary bodies in the preparations was infective.
Hospital of The Rockefeller Institute for Medical Research, and the Laboratories of the International Health Division of The Rockefeller Foundation, New York.
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JE
Smadel
T M
TM
Rivers
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EG
Pickels