114 II. FUNDAMENTAL STRUCTURE OF PROTOPLASM 



replica (22). 



An interesting fact has been found by Hosoya et al. (166) concern- 

 ing streptococcus haemolysin. When haemolytic streptococcus col- 

 lected by centrifugation were shaken with 10 per cent nucleic acid 

 solution for 20 minutes at 37^C, strong haemolytic power was found 

 in the solution after the bacteria were removed by centrifugation, 

 whereas no haemolysin activity was obtained if the bacteria were 

 washed with saline. Also powerful haemolysin was obtained when 

 nucleic acid was added to the culture media. This fact can be ex- 

 plained in the same way as the fact, above cited, found by Price 

 concerning a phage ; namely, the virus-like particles produced by the 

 bacteria are endowed with rigid structure by the nucleic acid to be- 

 come capable of exerting strong disturbing action on the blood cells. 



We were unable to separate haemolytic action of staphylococcus 

 haemolysin from virus-like particles containing lipids ; haemolytic 

 action would readily be inactivated when the particles were precipitat- 

 ed at the isoelectric point, whereas Wittier and Pillemer (167) have 

 succeeded in the purification of the haemolysin by isolating it from 

 the culture filtrate on precipitating at pH 4.0 in 15 per cent me- 

 thanol at -5°C. The expulsion of lipids to some extent seems thus 

 possible as in the case of some viruses if the treatment is made at 

 low temperatures. 



As already discussed, the protoplasm can be regarded as polymeri- 

 zation products of protein molecules possessing certain spatial arran- 

 gements of polar groups ; the pattern of the spatial arrangement may 

 differ with the kind of protoplasm or with the kind of cells, and each 

 kind of cells may have its specific pattern. In the protoplasm of a 

 certain cell, not only protein molecules but also other components, 

 such as nucleic acids, lipids, and sugars, have to be arranged so as 

 to be subjected to the specific pattern. Since the pattern of a cell is 

 to be changed into the viral pattern following the infection with the 

 virus, it may be expected that nucleic acid composition in a host cell 

 is deviated from the normal when the acid is synthesized in response 

 to the pattern of the protoplasm of the cell infected with a virus; the 

 viral pattern is to be replicated in the protoplasm so that the pattern 

 of the nucleic acid synthesized by the infected protoplasm must have 

 the same viral pattern. In agreement with this view it has been 

 claimed that nucleotide composition of a viral nucleic acid is character- 

 istic of the kind of the kind of virus ; in other words, the nucleic 

 acid compositions of unrelated viruses are demonstrably different, 

 whereas those of strains of a virus are indistinguishable (168). More- 

 over, it has been reported that phage DNA can be distinguished by 

 its hydroxymethylcytosine content from bacterial DNA which contains 



