It has been generally recognized that balneotherapy is effective for anemia, especially drinking of ferruginous spring is quite effective for iron deficiency anemia. Although considerable morphological researches have been done in the field, the reports dealing with the biochemical analysis are few in number. Accordingly, the mechanism of the action of hot spring on hematopoietic function still remains obscured. For this reason, the author has made an attempt to observe the iron metabolism in order to clarify the mechanism.
Part I is concerned with critical studies in methods for iron determination.
1) Hemolysis easily occurs in the process of separation of rabbit serum, but usage of a centrifuge tube coated with “solid paraffin” helps to prevent this. Another advantage of this simple method is to increase the amount of serum obtained.
2) Compared with sensitivities of various kinds of chromogenic agents employed in iron determination, nitroso-R salt (α-Nitroso-β-naphthol-3, 6-disulfonic Acid Sodium Salt) was greater in sensitivity than any other, as already reported by other workers.
As for the factors which have influence upon the time required for the complete color development in nitroso-R salt, the wave-length and the addition of hydroxylamin have been already described, and the author pointed out temperature as the most important factor. From the author's experiments, it was confirmed that when temperature was kept at 37.0°C, complete color development occurred and kept its stability in 10 to 15 hours.
3) The serum iron value, obtained by Ramsay's method, was easily influenced by hemolysis. Accordingly, the author tried to find the relation between the measurement error of serum iron and the degree of hemolysis.
This attempt may be convenient in estimating the iron value in a hemolysed specimen.
4) Considering the above, some alterations were made on the routine optical method for the determination of unsaturated iron binding capacity (UIBC).
The mean value for UIBC of healthy mature rabbits was 117.3γ/dl.
5) The author devised a new micromethod for determination of ferrous and ferric ion in iron solution.
This method is also applicable to ferruginous spring in which permanganate titration is not employed owing to coexisting reducing materials.

Reports are scant concerning the influence of hot-spring bathing upon hematopoietic function.
The author attempted to observe the variation in serum iron by single bathing. Since rabbit serum iron value is changeable by the way of venesection itself and this could be connected with iron metabolism in a case of acute bleeding, the author studies this problem in the preliminary experiment. The results obtained are summarized as follows:
1) In animal experiments (rabbit), it is desirable to limit the number of blood collection to two, and the amount of initial sample to less than 4ml for the observation of serum iron changes to minimize influence of the removal of blood. And it is necessary to give careful consideration to the difference in serum iron values if determination was made after the long interval.
2) In acute bleeding, the decrease of serum iron at the beginning of bleeding was due simply to hydremia, associated with the loss of blood. In the subsequent course, however, serum iron value tended to be considerably complicated by the flow of storage iron into blood stream or the stasis in hematopoietic organs, but, on the whole, serum iron tended to decrease gradually.
Iron binding protein, at the beginning of bleeding, decreased in proportion to serum protein and the rise in the saturation per cent was temporarily resulted from the tendency to maintain constancy in serum iron. Subsequently, the saturation per cent gradually decreased.
And in the early stage such as 2 to 3 days after bleeding, iron binding protein remarkably increased before the recovery of serum protein, and the rate of increase was 25.8per cent.
From the viewpoint of iron absorption, this may be considered to be a vital reaction which serves the purpose.
3) Reports are few concerning the serum iron value of the rabbit, and the author measured the serum iron values in 118 healthy mature rabbits. The results are as follows:
_??_251.4±13.2γ/dl _??_211.5±14.9γ/dl (by Yoshikawa's method),
_??_205.9±14.8γ/dl _??_ 194.1±15.2γ/dl (by Matsubara's method),
_??_198.5±11.4γ/dl _??_199.4±10.9γ/dl (by Noda's method).
4) Single bathing in “Genzc-yu” (acid vitriol spring), “Unagi-yu” (alkaline sulphur spring) and simple carbondioxated spring at Narugo Spring showed no significant influence on the serum iron in healthy persons and rabbits.

Morphological studies have revealed the fact that drinking of ferruginous Water is as remarkably effective as large doses of reduced iron in iron deficiency anemia, in spite of extremely slight quantity of iron contained.
The author attempted biochemically to observe the intestinal iron absorption, which is the first step in the effect of drinking of ferruginous spring. The results obtained are summarized as follows:
1) It was found that the routine experiments with rabbits on intestinal iron absorption in which the rise of serum iron or tissue iron was measured as an index of absorption were not sufficiently dependable for observing the immediate absorption from the intestinal tract.
2) Serum iron has been described by other workers, as a factor involved in iron absorption.
From the author's experiments on anemic rabbit phlebotomized, it was suggested that iron absorption was influenced by the level of unsaturated iron-binding capacity, and there is a definite relationship between them.
3) The author devised what is called “supra-surviving double intestinal loop method”, an improved experimental wethal in intestinal iron absorption.
(1) Based on the withdrawal-test, it was presumed that iron entering into blood stream and iron accumulated in the jejunal mucosa were included in the quantity of absorption obtained by this method.
(2) There was considerable variations in the absorptive power of individual animals. On the other hand, the absorptive capacity of the upper jejunum in the same individual showed no significant difference, and the neighbouring two portions showed still less difference.
Strictly speaking, in the upper jejunum, the absorptive capacity of the lower area was slightly inferior to that of the upper.
It may be caused by the difference in the distribution of mesenteric blood vessel.
(3) The quantity of absorption was approximately proportional to the concentration of iron solution, injected into the intestinal loop (under 1500γ/10ml).
(4) When original “Genzo-yu” (pH 1.65) or H₂SO₄ solution (pH 1.60) was injected into the intestinal loop, pathologically serious changes developed in the jejunal mucosa. But these solutions, when diluted 4 or 5 times, showed no change.
(5) Absorption was influenced by pH of injected iron solution, and it was most remarkably accelerated in iron solution showing a pH of 1.15, which caused serious changes in the mucosa.
On the basis of further studies into the conflicting phenomena, it was evident that iron absorption in these experiments was considerably limited by secretion of intestinal juice.
4) By comparing the absorption of ferrugino s spring (“Genzo-yu”) water with that of FeSO₄ solution of the same concentration by this method, no significant difference was observed.
5) In this experimental method, some problems to be criticized was elicited and the author feels that it is probably unreasonable to make an inference from these experiments on iron absorption under physiological conditions.

It has been widely recognized that the drinking of strongly acid hot spring water often causes gastrointestinal symptoms. However, the research in this subject has been distinctly sporadic.
Fundamental and clinical experiments were undertaken to ascertain the effect of the drinking of Tamagawa Spa on the gastrointestinal mucosa. The property of Tamagawa Spa, Akita prefecture, is acid vitriol spring whose pH value is 1.2, and it contains a large amount of hydrochloric acid and hydrogen sulfide.
1. Studies in Man
The changes of gastric mucosa in 36 subjects after the drinking of hot spring water were observed by gastrocamera or gastrofiberscope.
Varying degrees of hyperaemia were found in all subjects administered non-diluted hot spring water, whereas these change were markedly reduced in subjects administered two times and over diluted hot spring water.
No instances of erosion or ulceration were seen in any of the subjects.
2. Experiments in Animals
Twenty three healthy rabbits, orally administered non-diluted or diluted hot spring water for seven days were autopsied.
The changes of gastric mucosa were similar to those in man, and no significant influence on the jejunal mucosa was seen. Microscopically the affected mucosa revealed degeneration of the epithelial cells of gastric gland and edema of the submucosa.
Based on the critical review of former studies, several important factors were suggested to explain the occurrence of gastric impairment after the drinking of Tamagawa Spa water.

Our overall surveys of medical consultations for balneal therapy and of balneal curation at the Namekawa Spa, Yamagata Prefecture may be summarized as follows.
1) The Namekawa Spa is one in the Iegatayama Spa family located in the border of Fukushima and Yamagata Prefecture, which is saline hydrogen sulphide spring in character.
There is only one hot-spring inn in this resort (Fukushimaya Inn). It is rich in natural scenery, without the atmosphere of an amusements center and isolated from the wordly things. It is purely a spa for balneal treatment.
2) The larger number of visitors to this spa are from within the prefecture, especially from the towns and villages around the spa, but, because of its nearness to Fukushima Prefecture, quite a number of visitors are from this prefecture.
The visitors are mostly farmers, especially those of advanced age.
Half the visitors have been at the spa before and many of them are in the habit of revisiting the spa year after year.
3) A majority of visitors come to the spa for therapy of diseases and for recuperation, which shows that this spa has the character of balneal therapy.