The Size of Streptococcus Bacterio-phages as Determined by X-ray Inactivation.

THE SIZE OF STREPTOCOCCUS BACTERIOPHAGES AS DETERMINED BY X-RAY INACTIVATION INFORMATION about the particle size of bacteriophages has been obtained chiefly by ultrafiltration and centrifugation methods. Data of various authors, as oollected by Elford,l seem to indicate that the particles of each phage are homogeneous in size; and that particle size is a oharacteristie property of each phage. Coli-dysentery phages have particles ranging from 8-20 rnp (phage “X13”) to 50-75 mlr, diameter (phage “CM”). Staphylococcus phage “K” has a diameter of about 50-70 mu. The largest phage at present known has particles of 80-120 mu ( Subtilis phage) . broth in small celluloid tubes were exposed to x-rays (475 kv equivalent constant potential, 13 ma, .25 mm Cu plus .45 mm Al filter, 960 roentgens/min. measured in air at 37 cm focal distance, absorption and scattering corrections negligible). Afterward the phage content of each sample was determined by