264 
PKOGRESS OF MICROSCOPICAL SCIENCE. 
pairs are developed into appendages that have but a deciduous value, 
since they never fulfil the ofiice of permanent organs, and are gene- 
rally cast off with an early moult. 
This is observable within the ovum in Palcemon, Crangon^ &c., 
and also in the marsupial embryo of Mysis after it has quitted the 
ovum. 
The relation of these parts to the permanent organs the author has 
closely traced, and believes that he has demonstrated that the three 
pairs of mobile appendages in the cirripedal or Nauplius form of 
larva homologize with the eyes and two pairs of antennae, and not 
with the antennsB and mandibles, as stated by Fritz Miiller, Anton 
Dohrn, and others. 
The author, moreover, contends that the small pair of filamentary 
appendages seen on each side of the ocular spot, existing in the 
Nauplii of Cirripedes, homologize with the peduncular appendage 
existing in the larva of Caligus, the arm-like appendages in the pupa 
stage of Cirripedes, the peduncle of the stalked Cirripedes, and 
probably also with the long multiarticulate, antenna-like organs 
belonging to the fossil Pterygotus. 
He also demonstrates the origin of the nerves in a mass of cellular 
material that reaches from one extremity of the embryo to the other. 
This divides into parts corresponding to the various somites into 
which the animal divides. These masses gradually separate from 
each other as the animal increases in size, and concentrate into the 
several ganglia that form the great nervous chain. 
The author also shows the origin of the permanent organs of 
vision, and the manner in which the number of lenses increases with 
the growth of the animal, and traces the origin of several of the 
internal viscera and their mode of growth. 
He also figures, in minute detail, the larvae of an immense number 
of genera. 
An Examination of Br. Bastian's Experiments. — A very able 
critique on Dr. Bastian's views is that which was published some time 
since in the ' British Medical Journal,' by Dr. W. Eoberts, Professor 
of Medicine in Owens College, Manchester. He says : — Dr. Bastian 
has cited my name and quoted my experiments in a way that might 
make it appear that my investigations lend some support to his views 
on the origin of bacteria in organic infusions ; this is, however, not 
the case. On the contrary, the weight of my experiments is entirely 
against him and in favour of Pasteur's conclusions. I found, as 
others have done, that some infusions and organic mixtures produced 
bacteria after having been boiled for a certain time ; but I also 
invariably found that, if the boiling were sufficiently prolonged, no 
such result followed. All were rendered permanently barren — even 
Dr. Bastian's favourite turnip-and-cheese mixture. In quoting my 
experiments on alkalized infusion of hay. Dr. Bastian omitted to add, 
that in the same paper from which he was quoting, I furnished 
decisive experimental proof (not a mere explanation) that the germina- 
tion which took place after boiling was due to a survival of pre- 
existing germs, and not to a de novo generation. The results obtained 
