SCIENCE 



[N. S. Vol. LIV. No. 1387 



amphitheater of City Hospital and demon- 

 strated during the first hour the gross morbid 

 anatomy of several fairly typical heart lesions. 

 Recitation was then conducted by a student 

 on the normal physiology of circulation. This 

 was followed immediately by students' demon- 

 strations of the effects in dogs of hydroperi- 

 cardium, of acute myocardial degeneration, 

 of aortic stenosis and of aortic insufiiciency. 

 In line with the student's discussion of the 

 normal functions of heart muscle Dr. Scott 

 presented and discussed a few electrocardio- 

 graphic tracings. After a brief rest the stu- 

 dents then under Dr. Scott's direction ex- 

 amined three living patients exhibiting mur- 

 murs, thrills and cardiac arrhythmia. 



It is hoped that as the experiment in pro- 

 gressive education is more widely applied to 

 pathology the results will be improved, but 

 even with the experience now at hand there is 

 little doubt that this method has an applica- 

 tion in pathology and that in so far as it has 

 been attempted it has been proven to be emi- 

 nently successful. Certainly, the idea is prac- 

 ticable and its success will depend upon the 

 teacher's interest in the educational side of his 

 subject, his willingness to grant as large a 

 measure of freedom as possible to the stu- 

 dents' own effort, his keenness in careful su- 

 pervision and his confidence in the propriety 

 of the idea. 



Howard T. Karsner 



Lakeside Hospital, 

 Cleveland, Ohio 



A NOVEL MAGNETO-OPTICAL EFFECT 



(Further Investigations) 



In the former account of this novel effect, it 

 was pointed out that a microscopic examina- 

 tion of the iron arc smoke deposited on a glass 

 surface gave evidence of the existence of fine 

 particles of iron compound arranged in short 

 chain sections of bead-like relation. 



It is now thought that this peculiar forma- 

 mation may have its origin in the outer en- 

 velope of the arc flame where the particles 

 are formed, and where they are lined up around 

 the arc stream by the circular magnetism sur- 

 rounding the current conducted by the hot 



vapor stream of the arc. The particles, be- 

 ing magnetic, would tend to form chains or 

 rings surrounding the arc. These would not 

 be stable, however, but would float away as 

 they became shattered by gas currents, and 

 remain only as short lengths of particles held 

 together. To throw light on this possibility, 

 a small vertical, hollow cylinder of plaster of 

 Paris open above was arranged with iron 

 electrodes (for forming an arc) passing 

 through its sides and meeting in its center. 

 By passing the current of a storage battery 

 giving about 50 volts through them in con- 

 tact and separating them, an iron are could 

 be produced at will within the plaster cylin- 

 der. The dimensions of the cylinder were 

 such that a microscope slide 3" x 1" could 

 rest across the open upper end of the plaster 

 cylinder, only partly closing it, the slide lying 

 horizontally above the arc electrodes at a 

 distance of about 3 cm. Such a slide could 

 receive a layer of smoke on its under surface 

 when the arc was formed below it. The micro- 

 scope in that case showed only a confused 

 deposit. 



When, however, there was placed above the 

 slide a strongly excited electromagnet with its 

 poles resting on the upper sides of the slide 

 or close thereto, such poles being about 3 cm. 

 apart, a smoke deposit of a remarkable char- 

 acter was produced. Even as examined by the 

 unaided eye in diffused light, there was de- 

 cided evidence of a structure or striation. 

 When, however, the microscope was used, with 

 even comparatively low powers of about 300 

 to 400 diameters, there was disclosed a decided 

 striation seemingly composed of brownish par- 

 ticles in strings extending over the slide and 

 following the direction of the field. There 

 was noted a surprising regularity in the dis- 

 tribution or spacing of the strise, as if the 

 surface was covered with fibers laid on sys- 

 tematically side by side. 



There were, however, curious objects com- 

 posed of small spheres (evidently globules of 

 iron)' strung together in a line of two, three, 

 four or more, such spheres having no uniform 

 size. Most of these iron globule groups lay, 

 of course, in the field direction and were very 



