Metastasis of carcinoma to lymph nodes was studied from the viewpoint of correlation with the change of properties of lymph and histological findings by using Brown-Pearce rabbit cancer to which various conditions were added.
The results obtained are as follows:
1) If the properties of lymph were observed after production of artificial efferent lymph fistula in popliteal node following subcutaneous transplantation of Brown-Pearce rabbit cancer to the plantar pedis, the increase of number of cells, for instance, remarkable cell emigration of gross nucleous cells, degenerative cells, erythrocytes and leucocytes, were recognized after the third day of transplantation, but carcinoma cells after the tenth day.
2) When this lymph was injected in the anterior chamber of other rabbit eye in order to study the transplantation ability of carcinoma, the 13th's lymph caused a cancer. In the case of lymph node tissue suspension, a cancer was caused by injection of the 10th's material.
3) After the periodical dissection of regional lymph node lefting the plantar pedis carcinoma uninjuried, the tumor in popliteal wound was demonstrated in all cases which seemed to be a metastasis by lymph flow from the stump of the lymph vessel. Therefore, it would be suitable for surgical treatment of cancer that the dissection of the regional lymph node should be performed after the extirpation of the carcinoma.
4) Autopsy of the cancer animals after the dissection of the regional lymph node at various periods revealed that such a dissection is most effective for the prevention of general metastasis when it is performed until the 15th day after transplantation.
5) A metastasis which might be caused by the change of lymph flow after the dissecton of popliteal lymph node, i. e. normal lymph system, was observed.
6) No production of metastasis in the popliteal lymph node was histologically demon strated until the 20th day after the transplantation of carcinoma in the plantar pedis. Histological finding up to that time indicated only the remarkable enlargement of lymph sinus and the increase of reticular cells in lymph nodes.
7) If the tumor in the plantar pedis was incised, the degree of metastasis to the regional popliteal lymph node was enhanced in parallel with the increase of tumor cells and degenerative cells in the lymph.
8) The injection of suppurative germs into the tumor increased the number of tumor cell and also the metastasis to the regional lymph node. However, the transplantation ability to the rabbit eye in this case was lower than the others.
9) In the case of irradiation of Co⁶⁰-ray to the tumor, general metastasis was enhanced in case of less than 900 r. irradiation group and decreased in more than 1200 r. irradiation group. In the latter the increase of tumor cells as well as degenerative cells in lymph was recognized, but in the former the decrease of degenerative cells and the increase of tumor cells.

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In order to estimate the acoustic value of the middle ectosylvian gyrus (MES) which has been regarded as the primary projection area and termed AI, this investigation was performed.
This study mainly suggested by Tunturi's results obtained with the strichnine technique.
On the question of whether the cortical representation of the basilar membrane is topologic, in the MES of the dog, Tunturi has shown tones close together in frequency to be represented in a narrow band, low frequencies activate their bands in the more caudal portion of the gyrus, while progressively higher tones activate bands more rostrally located.
The situation in the cat may be similar, but the available informatics on this form does not yet warranted.
On the contrary, experiments in which auditory discriminations have been studied before and after ablation of auditory cortex have, for the most part, failed to show any permanent deficits of discriminatory ability resulting from the cortical ablations. For example, Girden discovered large initial losses in auditory sensitivity after incomplete bilateral ablation of the acoustic cortex in dogs, however, the limens returned almost to normal with continued testing. Kryter and Ades found that absolute thresholds of the cat are not impaired by bilateral ablation of auditory cortex.
In these cases, however, the destructions were not covered selectively all of the MES.
In this investigation, the dog was placed in a soundproof room with its head facing a loudspeaker and its left or right hind-leg being set to metal clip which can be charged with electricity.
A stimulus tone (from 125 cps to 8000 cps) is sounded for 2 to 6 seconds, directly followed by charge just strong enough to hasty flexion of the leg.
It continues to react, even through the tone be made progressively weaken, until the threshold of audibility is reached. After this training the dogs were subjected to partial or total, unilateral or bilateral ablation of the MES.
The results are summarized in the following.
(1) When the bilateral MES are ablated, various degrees of initial and permanent losses occur.
(2) Total unilateral ablation of the MES revealed that the effects produced on hearing, when compared one with the other, were not equal, and that one was dominant and the other was not. It seems that the unilateral dominance rested on what side the shock was given during training, and the contralateral MES of the shocked limb became dominant.
(3) Total ablation of the non-dominant MES causes no loss of hearing at all, or if it does the loss is temporary and is very slight, while that of the dominant MES causes a moderate and initial, slight and permanent loss. However, the hearing loss caused by bilateral total ablation of the both MES does not exceed the loss caused by total ablation of the domint MES.
(4) Partial ablation of the dominant MES caused no permanent loss. As for initial loss, characteristic hearing loss was observed in the removal of the more caudal portion of the MES in low frequencies, in the removal of the more rostral portion of the MES in high frequencies.
Although Girden suggested that the large initial losses might mean that some other principle than that underlying' the place theory' might be operative, it may be inferred that these characteristic initial losses are based on the tonotopic localization et the MES.
Moreover, when the residual portion of partial ablation of the MES was removed, initial transitory losses in hearing on all test frequencies were occured.
This observation suggested to us how the compensation for the cortical disorder upon auditory acuity might be performed.
(5) In total ablation of the MES partial amnesia for condioned stimulus was observable, while in partial ablation it was not always observable.

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In histological and electrophysiological studies, it is well known that acoustic trauma, represented by occupational deafness, originates in injury of the hair cells. However, it has not been satisfactorily answered why the hair cells are severely damaged by intense sound stimulation.
Considering the auditory mechanism of the cochlea from the electrophysiological point of view, vibrations of the basilar membrane during sound stimulation generate cochlear microphonics and summating potential at the hair cells with the aid of endocochlear DC potential, which originates in the stria vascularis and is maintained by the cochlear partitions. Therefore, an obstacle at any part of the cochlea may secondarily cause a functional impairment of the hair cells. In view of these findings, I attempted to elucidate the etiological origin of acoustic trauma from observations of cochlear microphonics, endocochlear DC potential and cochlear blood flow during and following sound stimulation.

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