As a result of investigations on the modes of ascaris infection in Japan, the following facts were found to be important factors.
1) The soil of vegetable fields contains abundant ascaris eggs: 2.8 per 1g of the dried soil, and 36.8% of the total eggs found were embryonated.
2) Those eggs are brought into houses adhering to the soles of shoes or carried by strong wind. The latter, especially in the early spring, seems to be one of the most important factors which causes the infection of ascaris.
3) In farm-villages, where the sanitary senses of people and the sanitary conditions of living fall much behind, the eggs on the fields may be drifted into drinking water by heavy rain or carried directly to mouth by tips of fingers after the work in the field.
4) Vegetables, especially leafy vegetables, are much contaminated by ascaris eggs and among all the vegetables leaves of radish, Tsukena, leaves of turnip, Hakusai and Shakushina seem to be the most responsible for the infection of ascaris. The asc ris infection from vegetables seems to occur most frequently in spring and autumn when those leafy vegetables appear on the market in large amount and the climatic temperature is sufficiently high for the development of ascaris eggs.

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We have presented here a brief introduction of immunization experiments of the typhoid disease carried out in our laboratory during the past twenty years, and discussed the difference of effectiveness between the live and killed vaccines. We think there are still many unsolvd problems about the infection and immunity of the typhoid which must be studied with a new idea under the cooperation of investigators from many fields of the science.

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(1) Sodium 3-phenylazonaphthionate shows a remarkable effect on the Japanese encephalitis virus in vitro and in vivo. Sodium 3-phenylazonaphthionate possesses virucidal, protective and curative effects against the neurotropic virus and has a low toxity.
(2) It is assumed that the antiviral activity of sodium 3-phenylazonaphthionate might be caused by direct interaction of the compound and the virus.
(3) Sodium 3-phenylazonaphthionate is of promise for treatments of diseases caused by small neurotropic viruses.

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In order to make experimental studies of the mechanism of the infection and manifestation of intestinal bacterial diseases which may be regarded as fundamental for the studies of bacteriological physiology of the intestines, we made 4 coliform strains selected at random resistant against streptomycin and compared their biological and immunological characters with those of their original strains.
We gave the coliform bacteria resistant against streptomycin (L.S.) to newborn babies and infants and observed their persistence in their intestines by cultivating these bacilli in their feces on Endo medium Containing 1000γ per c.c. streptomycin.
1. L.S. was orally administered to 73 newborn babies and infants under various conditions and its attitudes as to its growth and persistence in the intestines were persued.
2. L.S. which was given to 19 newborn babies persisted in the intestines for a relatively long time, namely, for more than 10 days, in 16 cases. The conditions of intestinal flora in these newbon babies before L.S. was ingested seemed to be the only factor that decided persistence in the intestines.
3. In 35 infants of the first group, the ingested L.S. were observed to proliferate transiently for the first one or four days and then disappear in a short time. In two cases of four patients with diarrhea, L.S. showed a weak tendency to persist in their intestines.
4. On the other hand, in eight infants of the second group, L.S. ingested with streptomycin showed an increase in persistence. This result was almost the same with that in the newborn described above.
5. With seven infants of the third group, when the L.S. in their feces wes found gradual decrease in number, administration of streptomycin prolonged its persistence. This result suggests that by creating a certain artificial condition in the intestines a carrier state of any non-resident coliform bacteria can be produced quite similar to that of dysentery bacteria.
6. Artificial replacement of resident coliform bacteria in an indiv dual caused no clinical symptom at least in our experiment if no other factor is present. It is also interesting fact that four patients with diarrhea, though injested with L.S., did not show any increase in diarrhea, but there was some improvement in clinical symptoms. Whether or not natural replacement of resident coliform bacteria in an individual causes diarrhea remains to be studied in the future.
We are grateful for kind advices of Prof. B. Nakamura, department of pediatrics and of Prof. D. Ushiba, department of bacteriology. We wish also to acknowledge that this study was supported by the government grant in aid for scientific researches.

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