SCIENTIFIC SUMMARY. 
505 
sulphide of carhon was placed beside him. For a few moments the animal 
remained perfectly quiet, seeming to take in long breaths ; in about half 
a minute he began to rush wildly about, as if trying to avoid the vapour ; 
soon, however, he became calmer, he had a few convulsive fits, and then he 
fell upon his side, still breathing. However, in a very short time respiration 
ceased, and the rat died in four minutes from the commencement of the 
experiment. On making a post-mortem examination, M. Cloez found that 
the whole tissue of the lung was congested, the brain presented no distinct 
lesion, the cavities of the heart were filled with a blackish blood, the right 
auricle continuing to contract for more than two hours after the death of 
the animal. The blood globules, as seen under the microscope, were not 
altered in form or general appearance. 
Action of Different Coloured Lights on the Betina. — It is known to 
physiologists that when a ray of light falls upon the retina, the impression it 
produces remains for a definite period, according to calculation about the 
third of a second. It is this fact which is used to explain why a burning 
brand, when twirled rapidly round, gives the appearance of a ring of light. 
But till quite recently it had not been shown whether the different colours 
of light had the same degree of persistence upon the retina. The subject has 
quite lately been taken up by the Abbe Laborde, who shows that, just as the 
prism separates the colours at different angles, so the retina absorbs the 
colours, or the impressions produced thereby, in different times. In con- 
ducting his experiment to prove this, the Abbe receives the sunlight through 
an aperture in a shutter into a darkened chamber. The aperture is about 
three millimetres wide by six -high. In the course of the beam and in the 
middle of the chamber there is placed a disk of metal, the circumference of 
which is pierced by apertures corresponding to the aperture in the shutter. 
This disk is caused to revolve by clock-work. Behind the disk is placed a 
plate of ground glass to receive the spot of light. The disk being then caused 
to revolve rapidly, the spot appears at first white, but as the revolutions 
become more rapid the borders of the spot and the colours which successively 
appear are in their order of succession as follow : blue, green, red, white, 
green, blue. — Vide Comptes Bendus. 
Contractile Corpuscles of the Colostrum. — According to the inquiries of 
Herr Strieker colostrum contains two varieties of corpuscles, which are 
interesting objects when viewed under the microscope. The corpuscles at 
first change form and then allow fatty globules to escape, and hence the 
author concludes that the envelopes of the cells must be made of some very 
plastic substance, since they show no indication of rupture. Contractile 
corpuscles have been seen by Herr Strieker in colostrum ; these resemble the 
same bodies in pus and blood, and are capable of peculiar amoeba-like move- 
ments, and throw out prolongations of a sarcode-like material. To witness 
the appearances which Herr Strieker describes it is necessary to keep the 
colostrum at a temperature of forty degrees centigrade. 
The Contractions of the Heart. — Dr. Paton, of Toronto, gives a paper 
detailing many experiments and observations upon the movements of the 
heart. The essay is published in full in the Dublin Quarterly J ournal of 
Medical Science, hut the more important conclusions are as follows : — 1. The 
dilatation of the ventricles is synchronous with the contraction of the auricles. 
