POPULAR MISCELLANY, 



403 



POPULAR MISCELLANY. 



What Medicine owes to Galileo. — In a 



lecture on the history of instruments of pre- 

 cision in medicine, a synopsis of which is 

 published in the Medical Record, Dr. S. 

 Weir Mitchell gives to Galileo Galilei the 

 credit of having contrived the first instru- 

 ment of this kind, viz., the pulsilogon. De- 

 siring to apply some test of the regularity 

 of the swing of the lamp-pendulum in the 

 Pisa cathedral, he is said to have used that 

 most wonderful of clocks, the pulse, for that 

 purpose. This was a grave moment in the 

 history of medicine — "the birth of pre- 

 cision," says Dr. Mitchell. From this use 

 of the pulse as a test of the regularity of 

 the pendulum he was led to use the pendu- 

 lum as a measure of pulse-rate — thus mak- 

 ing the pendulum a pulsilogon. The method 

 of using it was most ingenious. Having al- 

 ways a pendulum of equal weight, he set it 

 swinging, and then shortened or lengthened 

 the string until the beats corresponded with 

 those of the patient's pulse. Then he meas- 

 ured the length of the string, and one per- 

 son's pulse would be represented arbitrarily 

 but most precisely by say ten inches, an- 

 other's by eight inches, and so on. Galileo 

 seems to have given little thought to the 

 perfection of this instrument, and does not 

 speak in any of his essays of the medical 

 use of the pendulum. Many years later 

 Sanctorius described an instrument for meas- 

 uring the pulse which was in no respect 

 different from that of Galileo, and which 

 was called by the same name — pulsilogon. 



Plaut-Respiration. — From experiments 

 made by Mr. J. Jamieson, and published in 

 Nature, it would appear that fresh sections 

 of many fruits and other vegetable struct- 

 ures, as potato, give the. characteristic re- 

 actions of ozone, viz., causing separation 

 of iodine from iodide of potassium, and 

 turning tincture of guaiacum blue, the in- 

 tensity of the reactions depending mainly 

 on the comparative freshness of the fruits 

 and vegetables. Mr. Jamieson further finds 

 that these structures contain a substance 

 which acts as an ozone-carrier, or Ozon- 

 trdger, to use Schonbein's expression, a 

 substance which transfers ozone from hy- 

 drogen-peroxide, and similar bodies. This 



is shown by the fact that, if the guaiacum 

 is not blued at all, or only slightly, the blue 

 color becomes very marked when a drop 

 of ethereal solution of hydrogen-peroxide is 

 added. From these observations the author 

 infers — 1. That the oxygen inhaled by liv- 

 ing plants, and even by pulled fruits, for a 

 time is ozonized, probably by entering into 

 loose combination, as is the case with oxy- 

 gen in the blood of animals ; and, 2. That 

 it is probable that the ozone-transferring 

 substance existing in almost every fresh 

 vegetable structure is that with which it is 

 loosely combined, as the oxygen in the 

 blood is with the haemoglobin of the red 

 corpuscles. This element in plants is grad- 

 ually destroyed as decay comes on, and 

 ceases to perform its ozone-transferring 

 function when the fruit, etc., containing it 

 is cooked. It is not chlorophyl, as is 

 shown by its situation, and it seems to be 

 intimately associated with the vascular 

 tissue. From analogy with the animal sub- 

 stances, haemoglobin, fibrin, myosin, etc., 

 which have a similar action, it may be pre- 

 sumed to be proteinaceous, though the au- 

 thor is unable more exactly to indicate its 

 chemical and other characters. 



Growth of Mining Engineering In the 

 United States. — Thirty years ago the pro- 

 fession of the mining engineer was almost 

 unknown in the United States ; to-day the 

 American Institute of Mining Engineers 

 numbers over 700 members. The state of 

 things which existed thirty years ago. will 

 be understood from the following passage, 

 which we take from Mr. E. B. Coxe's presi- 

 dential address to the members of the In- 

 stitute at its last meeting: "Of the few we 

 then had worthy of the name of ' mining 

 engineer,' some studied in the Continental 

 academies, and others were graduates in 

 the school of practical experience, and had 

 learned their profession in mines and smelt- 

 ing-works. Their work consisted princi- 

 pally in making surveys and maps of mines 

 and mining properties, geological reports, 

 and analyses of ores ; but the mining engi- 

 neer, whom we often meet with now, who 

 has studied chemistry, physics, mineralogy, 

 geology, mechanics, and drawing ; who is 

 more or less familiar with machinery and 

 its construction, and with the practical 



