852 



SCIENCE. 



[N. S. Vol. XV. No. 387. 



greatest advancement in medicine. It has 

 been the means of discovering bacteria and 

 showing the minute cells of the body tis- 

 sues. Accurate medical diagnosis now re- 

 quires that the bacteria and cells must be 

 counted and measured, demanding of the 

 physicist a further improvement of this 

 essential instrument. The spectroscope 

 has been used recently for the analysis of 

 blood and presents a field for medical dis- 

 covery. 



Many physical instruments have been 

 adapted to the uses of medicine and have 

 been given special names. 



The cyrtometer for measuring the cui-ves 

 of the chest, and the cesthesiometer for de- 

 termining the sensitiveness of the skin, the 

 cardiometer, and the pelvimeter are all 

 only calipers of different designs. Hy- 

 drometers and certain graduated vessels 

 are called lactometers, saccharometers, or 

 albuminometers to indicate their special 

 uses. The spirometer, which measures the 

 capacity of the lungs, is usually a modified 

 form of gas meter. " The sphygmograph, 

 which records the pressure of the blood, is 

 a registering pressure gauge. The hsemo- 

 globinometer, for measuring the amount 

 of hffimoglobin in the blood, depends on a 

 photometric comparison. In general sur- 

 gery, levers, screws, clamps, pumps and 

 other mechanical devices are used in many 

 forms. In orthopgedic surgery in partic- 

 ular complicated mechanical appliances 

 are employed. These consist of clamps 

 braces and screws which are put together 

 in a variety of combinations. A special 

 appliance is often required for each ortho- 

 pedic case, requiring of the surgeon a 

 knowledge of the principles of mechanics. 



In the study of the ear the tuning fork 

 is used for producing uniform waves of 

 sound, and the acoumeter for measuring 

 the acuteness of hearing, the manometer 

 and the otoscope for observing and testing 

 the mobility of the aural membranes. In 



the study of the eye a special photometer 

 is used for determining sensitiveness to 

 light, the ophthalmometer for measuring 

 corneal images, the perimeter for measur- 

 ing the field of vision, and the astigmom- 

 eter for determining the amount of astig- 

 matism. 



Applications of Electricity. — The appli- 

 cations of electricity in medicine are in- 

 creasing daily. In electro-therapeutics the 

 direct and alternating currents have been 

 used for many years, and recently the high 

 voltage discharge from the static machine 

 has proved valuable for the treatment of 

 certain diseases. Electricity is used for 

 cauterization, for eradicating tumors by 

 electrolysis, and for illuminating the in- 

 terior of the body in surgical operations. 

 It is used in the production of X-rays, 

 which are constantly employed in both 

 medical and surgical diagnosis. No little 

 electrical knoAvledge is required to operate 

 X-ray apparatus. This knowledge must 

 be practical as well as theoretical. In per- 

 forming the electrical experiment in the 

 physical laboratory the student uses, and 

 becomes familiar with, various kind of bat- 

 teries, different types of galvanometers, re- 

 sistance boxes, switch keys, and various 

 other forms of electrical apparatus. Some 

 of this apparatus is always encountered 

 when an electrical current is used. These 

 are but examples showing the practical 

 utility of a laboratory course of physics in 

 medicine. 



In Conclusion.— The study of medicine 

 is long and difficult, especially when two 

 years of hospital service are superadded 

 to the course before private' practice is be- 

 gun ; yet if a laboratory course of physics 

 can be made of much value, the short time 

 spent on it, for example thirty-six hours, 

 seems a comparatively small part of the 

 three or four years of study that are re- 

 quired in medical schools. In 1899 the' 

 total amount of work demanded of medical 



