SCIENTIFIC SIJMHAEY. 
135 
result of his experiments, that he has now ascertained beyond all doubt that 
creosote is not a universal or permanent preservative of timber used in 
marine works. 
Anatomy of Sponges. — Dr. Bowerbank, who is well known to have long 
paid much attention to this lowly order of organisms, rejects the term 
Amorphozoa, or shapeless animals, proposed by De Blainville, adopting 
instead that of Dr. Grant, viz., Porifera, as the porous mode of imbibition 
of nutriment is universal in the class. He divides sponges into three 
classes, according to the nature of the skeleton, placing those first which 
contain calcareous spicula, the siliceous sponges second, and those 
with a horny structure, formerly placed first, are degraded to the lowest 
rank. 
Physiological Teaching in the Higher Schools. — Dr.Acland, Regius Professor 
of Medicine at Oxford, has addressed a letter to the teacher of physiology in the 
grammar school of Magdalen College, in which he strongly advocates physio- 
logical study ; and, as the best method, he recommends the collection of the 
Fauna and Flora of the neighbourhood, dissections of common animals, and 
microscopic research. He proposes to have precise osteological monographs 
of common typical animals, written by experienced physiologists,, and illus- 
trated with objects, instead of plates, which, though they would be more 
costly, would at the same time be more durable. In connection with this 
subject, we may call attention to the useful and interesting series of illus- 
trative dissections, by Mr. Charles Robertson, of the Oxford University 
Museum, which may be seen in the Educational Department of the Great 
Exhibition. These are precisely the kind of illustrations required, and might 
be prepared in any number by Mr. Robertson, or by Mr. Flower, of the 
Royal College of Surgeons. 
POSTSCRIPT. 
Since our Astronomical Summary went to press, the following ad- 
ditional intelligence has been forwarded to us ; — 
A new planet has been discovered by M. Luther, but, being near the 
position of the lost “ Daphne,” it has not yet been decided whether it is the 
latter or a hitherto unknown object. 
The transits of Titan’s shadow have become a matter of some curiosity 
during the disappearance of Saturn’s ring. It has been placed beyond doubt 
that they are well seen even in common telescopes. On April 15, Mr. 
Gorton observed this phenomenon with a telescope of 3-J- inch aperture, 
and a power of 170 and afterwards of 100, and says that the shadow of 
this satellite was almost as easily seen as a similar appearance on Jupiter. 
Mr. Dawes computes the synodic period of this satellite at 15°, 967. The 
latter observer considers, from recent observations on the ring of Saturn, 
that this portion is of almost inconceivable thinness, and much less than 
the forty miles ascribed to it by Professor Bond. Mr. Dawes imagines, also, 
