98 
POPULAR SCIENCE REVIEW. 
competent engineer for the instruction of others ; and in regard to riveted 
joints, which are often very carelessly arranged, Mr. Reilly proceeds on 
principles not only original and sound, hut in advance of current practice. 
MEDICAL. 
The Sphygmograph invented by Galileo. — It would seem from a letter of 
Mr. Charles Williams, in the “Lancet” of November 26, that Galileo really 
devised an apparatus for estimating the velocity of the pulse. Whether his 
instrument and the present one are the same is a question, but there can be 
no doubt that a sphygmograph of some kind or other was devised by 
Galileo. 
Photography in Medicine. — From the same number of the u Lancet ” we 
learn of the establishment in America of a u Photographic Review of Medi- 
cine and Surgery.” It is to be published once every second month. It 
contains four photographic plates. 
Substitution of Salts in the Bones. — The 11 Lancet ” of December 1 records 
some experiments that have been made in the course of the past year by M. 
Papillon, and which are recorded in the “ Comptes Rendus.” In one of 
these a young pigeon was dieted on distilled water to which hydrochlorate, 
carbonate, sulphate, and nitrate of potash were added, and with grain made 
into a paste with strontia. The bird remained in perfect health for nearly 
eight months, when it was killed, and an analysis made of its bones, with 
the following results : in 100 parts there were of lime 46-75, of strontia 
8*45, of phosphoric acid 41*80, and of phosphate of magnesia 1*80 ; residue, 
1*10. In a second experiment a white rat ten days old was subjected to a 
similar regimen, except that phosphate of alumina was substituted for the 
strontia given to the pigeon in the proportion of about a grain and a half per 
diem. The animal remained to all appearance in good health for about six 
weeks, when it died suddenly in convulsions. An autopsy showed the 
presence of intense enteritis. Analysis of the bones showed that in 100 
parts there were of alum 6*95, and of lime 41-10 parts. Another animal of 
the same litter was supplied with phosphate of magnesia instead of phos- 
phate of alumina, and was killed at the same time. Analysis of its bones 
showed the presence of magnesia in the following proportions in 100 parts : 
magnesia 3-56, lime 46 15. In all the animals the appearance presented by 
the bones was natural, and they seemed to possess their ordinary physio- 
logical peculiarities. 
Detecting the Blood of Animals. — It would seem that the questionable 
discovery of Herr Neumann has received confirmation by Dr. Day, of 
Geelong Institute, viz. that the picture or net- work formed by human blood 
can be distinguished under the microscope from that which is formed by the 
blood of other animals. He says he has repeated the experiment, which is 
(i wonderfully simple,” almost every day for the last two months, with in- 
variable success. A small drop, not a mere speck, of the blood is to be 
placed on a microscope-slide, and carefully watched, at a temperature of 10° 
or 12° Reaumur (=54-2° to 59° Fahr.), until the picture or net-work formed 
