The author has examined in detail the blood capillaries supplying the spiral ligament, especially those in the stria vascularis which have lately been a center of attention and was regarded to exert a delicate influence upon the internal ear mechanism: the calibre of each capillary in each turn of the cochlea was measured and the action of certain drugs on all these capillaries were evaluated.
Result
1) The guinea pig in which Preyer's pinna reflex is sensitive, the eardrum is normal, and is 450g in weight were used as an experimental animal.
2) The spiral specimen was made by prussian blue, and indian ink injection.
3) In the normal guinea pig the blood capillaries supplying the spiral ligament are divisible into four groups. The measurement with a micrometer has disclosed that of all these capillaries those in the stria vascularis are the largest calibred in each turn of the cochlea, followed, in the declining order of magnitude, by those in the spiral prominence, those in the depth of the spiral ligament and by those in the upper spiral ligament.
4) The capillaries resemble each other in their distribution and in the size of meshes in the networks they form, as examined in each turn of the cochlea.
5) Kallikrein dilates each capillary vessel in each turn, the capillary in the stria vascularis are more widely dilated than the rest, and the degree of dilatation was in the order of the basal, second and third turn.
6) Nicotinic acid dilates each capillary vessel, and has a more effective vasodilative action on the capillaries in the stria vascularis than the rest.
7) Chlorpromazine also dilates each capillary vessel. Chlorpromazine, like kallikrein and nicotinic acid, has a strong vasodilative action on the capillaries in the stria vascularis.
8) Kallikrein, nicotinic acid and chlorpromazine dilate the capillary vessel group in the spiral ligament, especially that of the stria vascularis. Kallikrein, nicotinic acid and chlorpromazine are vasodilative in this order of potency.
9) In animals administered adrenalin chloride the capillaries are constricted-the constriction is greatest in those in the stria vascularis and less so in those in the spiral prominence and they are all ill-stained ; and the capillaries in the basal turn of the cochlea are constricted most remarkably, those in the second turn less so, and those in the third still less so.
10) Of all the capillaries in the spiral ligament those in the stria vascularis are most highly susceptible to the action of a vasoconstrictor and of a vasodilator. The degree is in the order of the basal, second and third turn.
11) The capillary vessel of the stria vascularis in the basal turn may be affected at first by the administration of adrenaline in case of the interruption in blood circulation of the cochlea.
12) The author could presume that the vasodilators such as kallikrein, nicotinic acid, chlor-promazine was effective to the internal ear disease caused by the interruption in blood circulation.

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The increasing high-speed transport facilities and industrial machinery are afflicting a large proportion of the population with tremendous noises. A deafening noise causative of “Professional- schwerhörigkeit” is accompanied with coarse vibrations of low frequency, as has experimentally demonstrated by many research workers. However, possible injurious effect on the human body of a noise and a vibration combined remains unascertained despite a heated discussion on the subject by Wittmaack, Hössli and many later authors.
The epoch-making recent advances in histochemistry have added abunduntly to the morphology founded on microscopy and promoted, among other things, the study of nucleic acid.
The biological significance of nucleic acid, expounded for the first time by Caspersson, has come, with other cellular functions, to be taken up as an important them of research. Hydén, who studied the nerve cell in detail, tried to connect the protein metabolism with the function of the nerve cells. In this work I have examined the morphological and cytochemical changes on the spiral ganglionce lls exposed to experimental vibrations, then deduced the metabolism of intracellular nucleic acid.
The experimental animals, adult guinea pigs weighing between 300 and 500g, were kept exposed for 6 hours a day to vibrations (500 per minute frequency, 5 mm amplitude) caused with Morita's vibrater and the spiral ganglion cells from the animals were prepared into appropriate samples to examine the change produced in those cells by the continuous vibrations.
The sample were fixed in vivo with Carnoy's solution, fixed again postmortally, decalcified, embeded in paraffin, stained with Hamatoxylin-Eosin, Thionin, Methylgreen- Pyronin and examined in Feulgen reaction.
The tiny intracellular structures were examined further under a phase contrast microscop.
Result is
1. The spiral ganglion cells were observable in outline, but specificially when H. E. stained. Th. and T. B. stain showed the presence of RNA as the Nissl's body and, to some extent, the in tracelluar structures. The Mg-Py. solution stained RNA (in cytoplasm and nucleolus) and DNA (nu cleus) and then showed DNA in nucleus, specially nucleolus associated chromatin, in Feulgen reaction.
2. The vibration began to produce histological and histochemical changes (most of degenera tiv) in the ganglion cells of the upper whorls in two weeks or so.
3. Feulgen reaction disclosed in the 3 th week or so of the experiment that the nuclei and nucleoli were hypertrophied with the N. A. C. dick and deeper-stained which showed a hystochemical pic ture of either ribonucleic acid or probably protein beeing synthesized at an accelerated rate.
4. These histological and histochemical change were not, however, accompanied by an marked change in the power of hearing, probably because the injured spiral ganglion cells were compen sated for by the remaining cells growing in the protein-metabolizing activity, or because the vibration has a massaging effect on the ossicular chain as pointed out by Prof. Kawata.
5. The iujurious effect of vibration on the spiral ganglion cells is mechanical; the promoted activity of the protein forming system is presumabily an indication that the injurious effect pro duced by vibration is speedily eliminated with the cessation of the stimulating experimentation. However, continuous vibration, when combined with an uneasing tremendous noise, will have its impairing effect on the hearing organ aggravated.

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The author has examind the middle ear function before and after the laryngectomy and radical neck dissection of laryngeal cancer in 35 patients.
1) The retraction-grade of the tympanic membranes was measured by the use of the myringo- goniometer (Kawata-Ochiai).
The average retraction-grade of the tympanic membranes before the operation was 39 degrees in the right, and 32. 8 degrees in the left ear. The average retraction grade of the tympanic membranes after the operation was 36 degrees in the right, 29 degrees in the left ear.
After the laryngectomy the tympanic membranes were retracted inwards in 34 ears (48.5%) and were unchanged in 28 ears (40%).
2) The air-conduction threshold of 40 ears was measured by the NY-A audiometer. The hear ing acuity was unchanged in 25 ears (63%) and was impaired in 9 ears (23%) after the laryn gectomy.
3) The author modified van Dischoeck's pneumophon and attached a crystal receiver, a water manometer and a syringe to the 49-A audiometer (as shown in the photographs), that the pressure of the external auditory canal could be varried from 20cm H₂O to -20cm H₂O.
The auditory threshold for the 1024 cps tone was first measured by means of this pneumophon.
The author made the patients hear the tone, as a rule, of 30 to 40 db above the threshold and made them compare its loudness at 0cm H₂O and that at a certain auditory canal pressure.
By repeated questioning the zone of the clearest hearing (die Zone des deutlichen Hoerens, d. h. Z. D. H. nach Dischoeck) was obtained.
In the 11 of the 20 ears, Z. D. H. was unchanged befor and after the laryngectomy, and in 6 ears negative Z. D. H. increased.
4) In most patients whose hearing was unchanged after the laryngectomy, the nasal cavities were clean, and the patency of the auditory tubes and Z. D. H. were unchanged before and after the laryngectomy.
In 23% of the patients the hearing was decreased after the operation. In most of them nasal secretion and malform of the nasal cavities were found and the patency of the auditory tubes was bad.

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