抄録
We have found a heat susceptible character of the h mutant derived from the Kr(h) strain of S. sendai (S. 71 strain) phage.
This character always accompanies the h character in the mutation (h)⇔h.
On the other hand this character can be introduced into the progeny of a cross with h+.
Therefore it can be presumed that the genetic factor contorolling the heat sensitivity of this Kr phage may compose a complex with the gene controlling the h characte.
Experiments concerning the problem whether these two loci can be separated or not are still being carried on. There have been observed several experimental results, which can support indirectely the possibility of the separation of these two loci.
We believe that the extremely high susceptibility of this virus can at least allow fluther investigation with respect to the heatsensitivity of the bacterial viruses.
