330 
OWEN’S POSITION IN 
since the establishment of the cell theory/ Its 
importance as a factor in every theory of heredity 
is obvious ; and it must have an equally im- 
portant influence upon all theories of prolifera- 
tion. But, for the present, I must express the 
opinion that it affords very little more help 
towards a scientific explanation of the phenomena 
of ‘ Parthenogenesis ’ than Owen’s theory afforded 
in the infancy of histological inquiry. Except by 
the help of assumptions, of which there is no 
proof, I do not see that modern speculation, at 
present, gives us any better explanation why 
the leaves of some plants prolify readily and 
regularly, while those of others never do so ; or 
why female cockroaches never exhibit sexless pro- 
liferation while queen-bees always do so. The 
ingenuity which fits hypotheses to facts by the 
help of other hypotheses is always worthy of 
admiration ; but, if it is to be useful, its purely 
speculative character should never be lost sight 
of If science is to retain its strength, it must 
keep in touch with the solid ground of observation. 
In reading some of the biological literature of 
the present day, I sometimes rub my eyes and 
wonder whether I am not dreaming of the good 
old days of the NahtrpJiilosophie. 
In the preceding pages I have endeavoured to 
’’ I refer to the morpho- by this name ; not to any hypo- 
logical generalisations known theses based upon them. 
