
FINAL DECISIVE EXPERIMENTS 291 
be solely due to their ultimate molecular com- 
position. 
And when we think of the marvellous molecular 
complexity of protoplasm, and the innumerable 
variations of isomeric type that would be possible in 
new-born living units, we may see our way, in a 
measure, to understand the existence of such countless 
transitional variations in form and in property as 
are to be found among Micrococci, Streptococci, 
Staphylococci, Bacteria, Bacilli, Vibriones Spirille, 
etc.—and such as bacteriologists describe in their 
text-books. 
My point of view is that these multitudes of varied 
forms and properties may be found in new-born 
living units, altogether apart from heredity ; just as 
the multitudes of new-born crystals, when they 
appear, have their own exact angles between their 
facets, and their own optical characters, whenever 
they are formed under similar conditions and at 
whatever intervals of time. There is one important 
difference, it is true, between the two kinds of units. 
The simpler molecular composition of the crystal, 
which is a statical aggregate, does not predispose to 
change; while the infinitely more complex molecular 
architecture of the living unit favours change in form 
and in property under varying external conditions, 
as bacteriologists have long ago found—though with- 
out such change in conditions they continue to 
“breed true. 
I have, however, elsewhere endeavoured to show, 
not only, that Bacteria of different kinds, Torulez and 
