THe Microscope. 225 
apt to occur with other methods of staining, and the ease with 
which the depth of coloring may be regulated, as well as the 
reliable work for time being. A novice need not dread or pass 
over bacteria as difficult objects to obtain or prepare, especially 
when so easily and beautifully stained, and with the help of a 
small and inexpensive English work just out, “ Grove’s Synop- 
sis of Bacteria,” well illustrated, he can distinguish and name 
nearly all the species quite correctly, provided he has somewhat 
high powers to work with. 
ASPECTS OF THE BODY IN VERTEBRATES AND AR- 
THROPODS. 
A DER this title, quoted from Owen, Dr. Packard discusses in 
the September number of the American Naturalist some of 
the differences between the vertebrates and insects, especially 
those presented by the nervoussystem. The radson d’etre of the 
paper seems to be a criticism by Owen of a statement made by 
Packard that “the brains and nervous cerd of the fish or man is 
fundamentally different, or not homologous with that of the 
lower or invertebrated animals.” 
Dr. Packard attempts to sustain his position, but it seems to 
the writer that he is singularly confused in his ideas of homol- 
ogy aud ignorant of some of the most important papers bearing 
on this subject, and the closely related one of the origin of the 
vertebrates. Besides the older papers of Semper and Dohm he 
seems unfamiliar with the following, which have a direct bear- 
ing on the subject in question: Balfour, chapter on “ theAn- 
cestral form of the Chordata” (Comp. Embr. ii p. 259, 1881); 
Dohm (Naples Mittheilungen for 1881 or 1882, the exact refer- 
ence is not at hand); His ‘‘ Untersuchungen tiber die Entwick- 
elung Von Knochenfeschen, u. a.” (Zeitsch. Anat. u. Entw. i 
1875); Hubrecht “on the Ancestral form of the Chordata” 
(Quart. Jour. Micros. sci xxiii 1883); Kiipffer “ Die Gastrula- 
tion an den Meroblastischen Eiren der Werbelthiere” (Arch. f. 
Anat. u. Phys. 1882); Sedgwick “on the origin of Metameric 
Segmentation” (Quarterly Jour. M. S. xxiv 1884); Whitman 
‘““Kmbryology of Clepsine” (Q. J. M. S. xviii 1878), and “arare 
form of blastoderm in the chick” (7. c. xxiii 1883) and Wilson 
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