303 ANNUAL OF SCIENTIFIC DISCOVERY. 



valuable moans of comparing the pulse in various individuals and 

 under various circumstances. Some interestin<; results have been 

 obtained by stud3iug the pulse of diseased persons, and the in- 

 strument has been found to exhibit phenomena in the pulse which 

 it was quite impossible to detect by the lingers. The " sphygmo- 

 grani " of a person alUiitcd with a certain disease of the heait, 

 for example, is found to exhibit a series of undulations, the ascend- 

 ing line of which is very long and tremulous, and but slightly 

 oblicjue, while the descending is abrupt and nearly perpendicular. 

 From this description it will ije seen that this promises to be a 

 valuable assistance to medical men in reducing their observations 

 to something like exactness. — Quart. Joiini. of Science, July, 1866. 



J\li/o</raj>li. — M. Marey has invented an instrument, on tJie jilan 

 of his sj)]iygniograph, which he ealles a myograph, and which 

 maivi's a drawing to indicate the movemc^nts of muscular libres 

 in their cdntractions. A muscular shock imparts a wave motion 

 to tht^ fibres; if a shock is prolonged till the muscle is fatigued, 

 tlie waves lose their ami)litude, and linally become extinct. A 

 slow succession of shocks is marked by long ascending lines, and 

 short descending ones ; a quick succession leads to equality in the 

 ascending ami descending lines; and when the shocks are too 

 quick for healthy action, — more than tiiirty-tvvo per second, — 

 a tetanic condition supervenes, and a straight line replaces the 

 •waved line. 



Sto7iiatoscope. — This is an instrument invented by Prof. Burns, 

 of Breslau. A platinum spiral wire (inclosed in a box-wood cup, 

 to prevent the transmission of heat), brought to a red heat by the 

 passage of an electric current from two of Middeldorps' ele- 

 ments, is placed in the mouth behind the teeth. The light re- 

 flected by a very small mirror is sufficiently intense to render the 

 jaw trausi^arent, so as to allow of the vessels proceeding to the 

 roots of the teeth, the smallest specks of caries, etc., becoming 

 visible. By reason of the transparency, even the labial coronaiy 

 artery maj', in some subjects, be seen at the level of the commis- 

 sure, and its course followed. The instrument is therefore likely 

 to form a useful means of exploration in dental aftections. 



Iridoscope. — A new insti'ument produced by M. Houdin, by the 

 aid of which an individual is able to see all that is going on in 

 his own eye. It is simply an oi^aque shell to cover the eye, 

 jiierced in the centre with a veiy small hole. On looking through 

 steadfastly at the sky, or at any ditt'used light, the observer may 

 watch the tears streaming over the globe, and note the dilatation 

 and contraction of the iris, and even see the aqueous humor 

 poured in when the eye is fatigued by a long observation. It is 

 needless to say, that with the aid of this instrument, a man can 

 easily find out for himself whether he has a cataract or not. If 

 he has, he will only see a sort of veil covering the luminous disk, 

 which is seen by a healthy eye. The instrument is simple and 

 curious, and will no douljt excite attention in those who are anx- 

 ious to know more of themselves. An " iridoscope " may be 

 readily extemporized by making a hole in the bottom of a pill- 

 box with a fine needle. 



