Discussion 157 



Table III (Van Bekkum) 

 Alkaline Phosphatase Reaction in Granulocytes 



The figures in brackets represent the number of observations. 



in Table IV, there is practically no delayed mortality in the case of 

 isologous bone-inarrow therapy, but after homologous and heterologous 

 therapy a large percentage of the mice die between the thirtieth and the 

 sixtieth day after irradiation. These data are also in agreement with 

 those of Dr. Loutit, although I think that our 1 00-day s survival rate is 

 slightly better. 



Table IV (Van Bekkum) 

 Delayed Mortality of Irradiated and Bone Marrow Treated Mice 



Bone marrow Number of survivals 



30 rf. 60 d. 80 d. 100 d. 



Isologous 

 Homologous 

 Heterologous (rat) 



Spiegelman: I might note first that I consider the transformation 

 hypothesis quite unlikely. However, it seems to me that your test for 

 its existence is insensitive, because you are demanding that the trans- 

 formation result in a complete conversion of the chromosomal apparatus, 

 and this is highly improbable. VV^e know that in bacterial transforma- 

 tions only a minute portion of the chromosomal material is actually 

 incorporated, and the number of characters involved is invariably 

 small, one or two. It would be better then to look at somewhat more 

 restricted changes in phenotype, for example, perhaps with respect to 

 the antigenic properties of the cell. A simple experiment perhaps is to 



