SCIENTIFIC SUMMARY. 
221 
ambient air causes all activity to cease (camplior, acetic acid, essential oils, 
&c.). As to the first cause of the motion, it is found in the reciprocal action 
of two fluid surfaces. It may be a phenomenon of capillarity, or of the 
superficial tension of the liquids. 
Electro- Conductivity of Pyrites. — M. H. Duffet, in the “ Comptes Rendus,” 
contends that the conductibility of iron pyrites is a true metallic conduc- 
tibility, very variable according to the physical structure of the specimen, 
but which, in a given crystal, is affected neither by the direction, nor the 
intensity, nor the duration of the current. 
Common and Magnetic Iron in the Atmosphere. — It is alleged by M. G. 
Tissandier, who, as our readers are aware, is an eminent balloonist, thatTn 
specimens of atmospheric dust examined by him he has discovered minute 
particles of magnetic iron ore, which he believes to be of cosmic origin. 
Influence of Forests on the Quantity of Pain. — The “Chemical News” 
says that the absolute quantity of moisture in the atmosphere appears to 
differ little at any season of the year in open grounds, and in forests. The 
relative moisture is, however, greater in forests, the difference being greatest 
in summer, and increasing with the elevation of the place above the sea-level. 
According to Ebermayer’s view, forests increase the amount of rain only 
by their action upon the relative moisture of the atmosphere. 
Spectroscopic Reactions of ILcemoglobin and its Derivatives. — M. C. Husson 
gives the following observations, according to a notice in the “Chemical 
News.” — Haemoglobin, on absorbing iodine, splits up into heematin and glo- 
bulin. This fact is proved by the spectral analysis, which gives between C 
and D the absorption ray of haematin, which does not seem to be affected by 
the iodine. Chautard has already shown that this element has no influence 
upon the rays of chlorophyll. The microscope also indicates the splitting up 
of haemoglobin. With bromide of potassium we obtain crystals of hydro- 
bromate of haematin, of a rosy tint. On treating blood with borax and 
glacial acetic acid, we obtain all the crystals described by MM. Robin 
and Verdeil in their a Traite de Chimie Anatomique ” under the name of 
hematoidin. Glacial acetic acid alone gives, without the aid of any other 
reagent, fine crystals of acetate of hemine. 
ZOOLOGY AND COMPARATIVE ANATOMY. 
Effect of Strychnia on Medusce. — An interesting paper, describing the 
development of Medusae, and the effect on them of certain poisons, is given 
by Mr. G. J. Romanes, F.L.S., in the Proceedings of the Royal Society 
(No. 165). He states that strychnia exerts a very marked influence upon 
Medusae. “Of the species I have met with Cyaneea capillata is the most 
suitable for showing the effects of this poison, from the fact that, in water 
kept at a constant temperature, the normal pulsations of this animal are as- 
regular as are those of a heart. Shortly after a solution of strychnia has 
been added to the water in which a specimen of C. capillata is contained, 
unmistakable signs of irregularity in the pulsation of the animal supervene. 
