262 THE NORTHERN MICROSCOPIST. 
after the water and “ weed” had been put into a “trough.” It was 
seen first in the state figured. The eggs within the empty body 
are manifestly the eggs of the Callidina ; but this in the sequel was 
not a matter of mere conviction, but became a demonstrated fact, 
when from one of the eggs the form seen in 6 emerged and mingled 
with its fellows. The other eggs never produced anything, pro- 
bably having been injured. They simply decayed and broke up. 
Then it became manifest that Dr. Bastian’s curious assumption of 
the heterogenesis of the tardigrade’s body substance into eggs, be- 
cause eggs appeared in and filled that “ body,” is refuted by many 
observations, and the cause of the appearance of Stentor, Rotifer, 
and other eggs within the carapaces of Tardigrades is explained by 
the observations of many. 
But it is still more curious to find that such absolute refutations 
as have been given by experts in their own several departments of 
biological research, of the assumed instances of Heterogenesis, pub- 
lished in the Beginnings of Life, have not in all minds suggested 
the need, in observation, of the extremest caution. How serious 
the resulting errors are, in only one direction, has been shown 
plainly by Prof. H. L. Smith,* of America, whose competence to 
write critically on the subject of Diatomacez will not be disputed. 
He has given an absolutely destructive detailed criticism of every 
important instance of the reputed transmutation of something else 
into Diatoms which Dr. Bastian has presented, and brings out 
clearly the mistake of attempting to infer the “heterogenetic” 
origin of vital forms of whose ascertained history the observer was 
ignorant. Professor Smith says, “I have probably witnessed more 
of the phenomena of conjugation and growth than any other per- 
son, and can affirm, without fear of being disproved, that 
any kind of transformation of Pediastree or Desmids into Diatoms 
never has happened—nay more, never will happen.” “I look,” 
he continues, “ more particularly to the evolution of Diatoms, fully 
convinced, however, that the errors of misinterpreting what he (Dr. 
Bastian) saw are quite as great with the Desmids as with the Dia- 
toms.” For example, Fig. 17, Plate V., is a reproduction of one 
of Dr. Bastian’s figures, which he declares represents, at ¢ ¢, the 
“heterogenetic” origin of Diatoms from the Cladophora filament 
A. Professor Smith says, poor as the cut is, we easily recognise 
the “pedunculated diatoms” as “ Acanthes exilis in its normal 
condition !” In fact, it constantly grows naturally thus on Clado- 
phora, Vaucheria, and other alge. But, because Dr. Bastian was 
not aware of this, he took the observation as a fine illustration— 
which in view of the facts we have no objection to admit—of 
AR Se ee ee ee ae ee ae eed 
* Archebiosis and Heterogenesis. Tye Lens, Jan., 1873, and Quart, Jour. 
Micro, Science, vol. xiii., p. 357, and note by Mr. yor Pg Bd peel 

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