SCIENTIFIC SUMMARY. 
403 
horse, and conversely. (5) In both animals variola may appear, sporadi- 
cally and epidemically. (6) When small-pox occurs among men, it often 
extends itself to other animals, or conversely, it may first appear among 
the latter and be communicated to the former. (7) The dangers of inocu- 
lation of variola in man have been greatly exaggerated, as any one who 
impartially considers the evidence on the subject will admit.— Vide Gazette 
Medicate , November and December, 1863. 
Cause of the Production of Scapho -cephalic Shulls. — Dr. Turner, of the 
University of Edinburgh, has written an exhaustive essay on cranial 
deformities, in which the above is well explained. It is a remarkable fact 
that in all scaplio-cephalic skulls the sagittal suture becomes obliterated 
in early life ; an entire conversion of the bone-forming blastema into bone 
occurs, and hence the cranium cannot be enlarged to any great extent in 
the transverse direction. Now, as the brain increases in size, it becomes 
necessary that the skull’s capacity shall also increase pari passu ; this 
increase cannot take place laterally, and hence the bone-developing plasma 
lying in the occipital and coronal sutures is obliged to undertake the 
labour of enlarging the brain- case, which thus becomes prolonged in the 
antero-posterior direction. — Vide Natural History Review , January. 
The Use of Nitrous Oxide in Dental Operations . — Under this title will be 
found a most interesting contribution to the Dental Review (Hardwicke), 
from the pen of Mr. Samuel Lee Rymer. The history of the employment 
of protoxide of nitrogen as an anasthetic is easily given, but the -writer 
does not at once concur in the opinions of his American brethren as to the 
efficacy of laughing-gas in dental cases. With a cautious reserve which 
does him much credit, he observes, “ I have not much doubt that transient 
anasthesia may, in almost all cases, be produced safely by the proper 
inhalation of the gas ; by which I mean not only the exhibition of pure 
nitrous oxide quickly, but the exercise of some discrimination in allowing 
its exhibition at all To arrive at a definite conclusion upon the 
safety of the nitrous oxide, perhaps the best mode of procedure would be 
to subject a number of animals to its influence, before experimenting 
largely upon the human subject.”— Vide The Dental Review , January, 
1864.' 
METALLURGY AND MINING. 
Direct Production of Wrought Iron and Steel in the Blast Furnace . — 
A very interesting method for obtaining the above result has recently 
been patented by Mr. Johnson, of Lincoln’s Inn Fields. The process 
consists essentially in the introduction of finely divided oxide of iron into 
the blast, which, of course, conveys it to the metal in the furnace. The 
result of this introduction of oxide is that the cast iron becomes decarbon- 
ated in the blast-furnace itself, without being placed in puddling or other 
furnaces. Any other oxide which acts in a similar manner may be 
employed with equal advantage, and other substances may also be em- 
ployed for the purpose of purifying the metal. The crucibles which are 
usually employed must undergo some modification in order to admit of 
the patefited system being carried into execution. It is thought advisable 
