ALG^ • 
337 
till then supposed distinct. Histories carefully followed out_, 
like that of the Protococcus by Cohn^ open up a page in the 
life-history of vegetable growth infinitely more expansive 
in its physiological bearings infinitely more expanding to 
the mind ; much more amazing in regard to the variations of 
nature than had been declared by the former observers,, who 
had not often looked beyond the state of the specimen before 
them^ and who had in that specimen excluded all other forms,, 
except those about the same size,, of the same colour^ and 
deriving evidently from the same stock. Beyond this their 
inquiries did not often extend. They were contented,, if they 
found a new form^ to place it in a group already established^ or 
to make a new genus for it^ without inquiring further; and 
then,, once placed^ its destination was fixed for a long period. 
Having thus had his attention directed to the basis upon which 
the groups of lower algas^, especially the Palmellaceae^ were 
founded^ the reader will probably see that if it were subsequently 
discovered that^ as far as could be distinguished by the micro- 
scope,, identical forms were produced by the higher plants^ a 
difficulty would immediately present itself during an obser- 
vation whether the so-called Palmellaceous plant were indeed 
a separate independent organism^ never altering its state^ or 
derived from a higher plant. 
It will perhaps not be surprising, that when I noticed that 
growths, indistinguishable from the lower algse, were to be 
produced from certain parts of the lichens, mosses, and certain 
other plants hitherto grouped as algae, but really quite distinct,* 
I should have ventured to question the possibility of identifying 
the so-called Palmellae, and kindred groups. While I did 
not deny the possibility, of the separate existence of these 
groups, I endeavoured to show how little reliance could be 
placed upon the hitherto accepted observations, and to urge 
upon observers to devote then* energies to the study of their 
whole history, rather than limit nature in the way already 
done. 
But the task is a severe one, requiring much patience, accu- 
racy of observation, careful delineation, by no means attractive 
to minds who wish to show early the results of their labours ; 
nor to those who delight more in definiteness and conciseness, 
than in following truth with hesitating steps ; who delight in 
subdivision rather than in synthesis. But by what other 
'''' “Jour. Microscop. Sc.,” 1860 (July and Oct.), 1861 (Jan.). Also in 
same Journal, on “Lyngbya Muralis,” 1861, and on “ Statospores of 
Volvox.” Trans. Linn. Soc., 1862, on “Gonidia and Confervoid Filaments 
of Mosses, and on relation of then Gonidia to those of Lichens and certain 
freshwater Algse.” 
