186 
“ 1. Not only Algae and Fungi, but Lichens also, are pro- 
vided with zoospores. 
“ 2. Zoospores have been discovered in three very different 
genera of Lichens, viz. Physcia, Cladonia, and Evernia; and 
as these genera were selected undesignedly, it is probable 
that zoospores exist in all other lichens furnished with 
chlorophyll. 
“3. We have demonstrated the identity of free gonidia 
with the unicellular Alga Cystococcus of Nageli ; consequently 
this is not a distinct genus, but only a phase of development 
of a lichen. 
“ 4. The culture of the freed gonidia of Physcia, Cladonia, 
and Evernia led us to expect that other lichens would afford 
forms corresponding with rudimentary Algae. Our researches 
prove this to be well founded. Vertical sections of the thalli 
of Peltigera and of Collema, cultivated on moist earth, showed 
the filaments in disintegration, the augmentation in size of 
the gonidia, and their transformation into glomerules com- 
posed of spherical cellules. The gonimic cellules of Peltigera 
and Collema continued to live when separated from the 
thallus : those of Peltigera were identical with an Alga called 
Polycoccus ; those of Collema produced organisms similar to 
Nostoc. Consequently these three genera of Algae, hitherto 
regarded as different and distinct, are in reality only the 
gonidia of lichens in a state of development when separated 
from the thalli which produced them,” 
Mierozoology. L’Origine de la Vie (preface par F. A. 
Pouchet.) By Georges Pennetier. 
This work, published by Rothschild, of Paris, gives a fair 
exposition of the views of the experimental heterogenists, 
amongst whom M. Pouchet is most prominent. All the old 
experiments, the precautions taken to prevent error, the con- 
ditions necessary for success, and the various ‘ forms’ ‘ spon- 
taneously’ generated, are here given in a well-w-ritten, popular 
neat little book. The figures, which are in the objectionable 
style of white on a black ground, are certainly inadequate, 
and can give but the vaguest notions. No new argument is 
added to the case stated by the heterogenists ; in fact, none 
can be. They say ‘ our experiments are perfect ; we exclude 
all possible error by admixture of atmospheric or other dif- 
fused germs, and yet in certain solutions we obtain life.’ 
There is no possibility of discussion with these philosophers ; 
all we should ever think of doing in the matter is to deny 
the accuracy of the experiment. Experiments prove next 
to nothing in this matter ; for an honest man must admit 
the vast possibility of error. The question of heterogeny is 
