SCIENTIFIC SUMMARY. 
333 
taintv with which this apparatus can be instantly laid upon the fine-adjust- 
ment wheel, or turned bach from it, is sufficiently evident. 
Importance of the Microscope in working at the Skull. — I)r. Kitchen Parker, 
F.R.S., the President of the Microscopical Society, recently read a paper on 
the above subject before the Society. He says it is all microscopic work j 
step by step everything- has to be made out by the most delicate micro- 
scopical manipuhition, and but for that instrument the whole matter must 
have been kept secret to the end of the world. It is impossible to overrate 
the value of such means that lead to such researches, for now we begin to 
see the absolute Unity of the Vertebrate Series — to say nothing of the other 
primary groups of animals. The highest type — the human — passes through 
every stage of morphological structure seen in the series beneath : it does 
not stop at these stages ; it does not utilise, so to say, the incipient struc- 
tures that are ready to be so used, but runs rapidly along its own line, 
choosing, as it were, and refusing, until at length the perfect man is attained. 
V et this perfection of parts, this production of a creature who in his lowest 
attributes is the “paragon of animals,” is not brought about irrelatively to 
the rest of creation ; it is merely an elected consummation of all that is 
highest and best in morphological structure. 
Bleaching JDiatomacece. — -The following note has been published by no less 
an authority than Dr. Maddox. From some experiments conducted lately 
in bleaching both marine and fresh-water forms, the use of chlorate of 
potash and hydrochloric acid appears to him as likely to prove very useful in 
the examination, not only of t e skeleton, but the disposition of the endo- 
chrome ) and it seems probable the same may be employed with success on 
the minute Algae and minute forms of organic life commonly accompanying 
them in the collection. The proportions used have been varied, but about 
40 grains of the crushed chlorate to 1^ drachm of the acid in 1 ounce of 
water, placed in a 2 or 3 ounce phial, closed with a waxed cork, may be 
taken as the average proportions : the action of the evolved chlorine com- 
mences after a short period, and can be watched or modified as required. 
The use of this mixture for the examination of chitinous structures in 
insects was advocated by Dr. Hicks ; but Dr. Maddox is not aware of its 
having been extended to the Diatomaceae ; therefore the suggestion is made- 
in the hope it may be found useful b} r those engaged in the examination of 
the organisation of these very interesting objects. 
PHYSICS. 
How to fix the Iron-filings acted on by Magnetism . — All our readers are 
aware how beautifully iron-filings arrange themselves when placed under 
the influence of the magnet. It is not such a simple matter to preserve these 
forms, and the following method, suggested by Dr. S. M. Mayer, in an 
article in the “ Chemical News,” June 9, seems an excellent one. It is as. 
follows : — A clean plate of thin glass is coated with a firm film of shellac, by 
flowing over it a solution of this substance in alcohol, in the same manner 
as a photographic plate is coated with collodion. After the plate has 
