PHYSIOLOGY. 



637 



Prof. Mills holds that these chambers do 

 constantly exercise an important influence on 

 pitch, and supports his position by citing ob- 

 servations or experiments which almost any 

 one may test for himself. Thus, while all the 

 other conditions are unchanged, by passing 

 suddenly from the arrangement of the supra- 

 glottic parts suited to the utterance of o (as 

 in " note ") to that form of the parts requisite to 

 sound e (as in " me "), a change of pitch will be 

 noticed which the most un discriminating ear 

 can not fail to appreciate. The same experi- 

 ment may be repeated in view of the laryngeal 

 mirror, when a change of pitch will be made 

 without any noticeable change in the glottic 

 appearance. Again, if the vowel a (as in " say ") 

 be sung at about the pitch of common conver- 

 sation, or rather higher, and a musical instru- 

 ment sound the note which seems best in ac- 

 cord with it, a departure from the note by 

 even half a tone will be found to alter slight- 

 ly the sound of the vowel. Hence, in account- 

 ing for pitch we must take into consideration 

 the condition of the supra-glottic apparatus as 

 well as the behavior of the larynx. The term 

 falsetto voice is used to designate a certain 

 quality of the voice not distinguished from the 

 natural voice by any fixed line, but overlapping 

 with it through a series of notes that can be 

 produced by either. The essential conditions 

 in the production of this quality are closure of 

 the glottis posteriorly to a variable extent, de- 

 pending largely on the pitch, but somewhat 

 different in extent in different individuals ; the 

 force of the blast ; and the manner of blow- 

 ing. Variable conditions are the compass of 

 the falsetto ; the extent to which the vocal 

 bands approximate posteriorly, and especially 

 anteriorly ; and the perfection with which the 

 vibration of the segmented portion of the vo- 

 cal cords can be effected. Almost precisely 

 the same conditions apply to the head-voice 

 production in females. A vocal register is de- 

 fined by Garcia as " a series of consecutive and 

 homogeneous sounds, rising from the grave to 

 the acute, produced by the development of the 

 same mechanical principle, the nature of which 

 essentially differs from any other series of 

 sounds equally consecutive and homogeneous 

 produced by another mechanical principle." 

 Garcia and Madame Seiler divide the registers 

 into the chest and the head register, with the 

 falsetto interposed between them. Madame 

 Seller makes a further division, and physio- 

 logically describes the registers as follows: 

 a. The first chest-register, in which the whole 

 glottis is moved by loose vibrations; &. The 

 second chest-register, in which the vocal liga- 

 ments alone act ; c. The first falsetto, in which 

 the edges alone of the vocal cords vibrate, but 

 the whole glottis is in action ; d. The second 

 falsetto, in which the edges of the vocal cords 

 only are used, and the vocal ligaments alone 

 are in action ; and, e. The head-tones, in which 

 the edges alone are vibrating while the liga- 

 ments are partially closed posteriorly. Prof. 



Mills accepts the division and definitions, as to 

 essential points, after having tested them on 

 fifty subjects. In conclusion, he suggests that 

 most writers on the physiology of voice appear 

 to have attached too little importance to the 

 wind-force apparatus and its action. Every 

 trained singer knows, or should know, that 

 correct breathing is, of all things, the most im- 

 portant in healthy and efficient vocalization. 

 The chest production, the head-voice so called 

 of males and high falsetto, cause in the subject 

 sensations very different, part of which are 

 referable to the larynx and to the v/ind appa- 

 ratus. It is a matter of observation that more 

 breath-force is required to produce a chest- 

 tone than a head-tone of the same pitch, and 

 less for the corresponding falsetto than for the 

 head-tone. But that there is some difference 

 in the manner of blowing that is essential to a 

 good achievement in these different produc- 

 tions is capable of proof by experiment on 

 one's own person. 



Formation of Urea. To determine in what part 

 of the animal organism urea is formed, W. von 

 Schroeder has made a series of experiments in 

 which blood was caused to circulate through 

 living organs, the amount of urea contained 

 being determined both before and after its pas- 

 sage. An experiment on a dog after the kid- 

 neys had been extirpated showed that urea 

 still accumulated in the blood. Ammonium 

 carbonate was added to a specimen of blood, 

 which was then parsed through an ox-kidney, 

 but afterward showed no increase in area. 

 Like experiments with dogs' kidneys gave the 

 same result. Hence it was concluded that the 

 kidneys are incapable of converting ammo- 

 nium carbonate into urea. Experiments were 

 also made with the livers of dead dogs into 

 which blood was injected by the portal vein 

 and taken out from the vena cava above the 

 diaphragm. In one experiment, blood to which 

 ammonium carbonate had been added con- 

 tained before injection -0442 per cent, of urea, 

 after the injection -0812 per cent. ; in another 

 experiment the increase was from "0538 to 

 1253 per cent., the solid matter in these cases 

 having only slightly increased. Blood without 

 the addition of ammonium carbonate was then 

 passed through the liver of a hungry dog, ?md 

 through that of one killed during the process 

 of digestion. No perceptible increase in urea 

 was noticeable in the former case, while in the 

 latter the content of urea rose from -0499 to 

 0636, showing that the liver is able to produce 

 urea from some substance formed in 'digestion. 



The method of the formation of urea from 

 ammonium carbonate, Von Schroeder holds to 

 be by the loss of water. 



Further light has been thrown upon the 

 formation of urea in the body by the researches 

 of E. Salkowski in regard to the behavior of 

 several amido acids. The sodium salt of me- 

 tamido-benzoic acid was given to rabbits and 

 dogs in quantities of two to ten grammes a day. 

 In the urine of the rabbits 5 per cent, was ob- 



