Various metabolic activities, independent of those of host cells, have been reported in some species of rickettsiae in vitro. These findings, though they contributed enough in differentiating rickettsiae from the category of virus, had been confined within exergonic reactions until Bovarnick (1959, 1960 a, b) reported the evidence of incorporation reactions in purified Rickettsia prowazeki.
An ability of purified Rickettsia mooseri to incorporate ³⁵S-methionine into its protein fraction in a medium lacking other complementary amino acids was evidenced by us (Fujita et al., 1959) .
In the present study, a protein specific incorporation of amino acid mixture uniformly labeled with ¹⁴C is reported together with the results on the ³⁵S-methionine incorporation. In contrast to the incorporation of ³⁵S-methionine, which is found not to be available as an estimation of protein synthesis, the incorporation of ¹⁴C amino acid mixture can be regarded as a rough estimation of protein synthesis taking place in a medium much simpler than that previously used by Bovarnick.
This incorporation of ¹⁴C was found to be able to couple with the phosphorylation of ATP, indicating that the oxidative phosphorylation reported by Bovarnick (1956) in typhus rickettsiae and by Myers et al. (1959) in Coxiella burnetii may have an important role in the protein metabolism of this parasite.

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In their studies on paracolon bacteria, Stuart, Wheeler, Rustigian & Zimmerman (1943) classified paracolon Aerobacter, which possessed the biochemical characteristics of Aerobacter except that they were late or non-lactose fermenters, into two divisions on the basis of their IMVIC system. Each division was divided into types, on the basis of other biochemical reactions, which were designated simply by the numbers of representative strain in each type. Of these, type 32011 was incriminated as an incitants of enteric disorders, since the type was isolated frequently from patients.
Independently of the studies by Stuart and his co-workers, Møller (1954) set up a group of Enterobacteriaceae, Hafnia group, of which the original strain was Paratyphus alvei. The establishment of the group was supported by Kauff mann (1954) who gave a species name, Hafnia alvei, to organisms of the group. Later, it was confirmed by Edwards & Ewing (1955) and Sakazaki & Namioka (1957) that type 32011 of Stuart and his co-workers was identical with the Hafnia group.
In spite of the biochemical studies, there have been little serological studies of the group. Stuart & Rustigian (1943) who studied serologically 149 strains of the biotype 32011 starting with 35 strains, reported that strains of the type were serologically heterogenous. However, they tested their strains only with the serum prepared with the type strain. In addition, the results of their work were not given in sufficient details to the antigenic analysis of strains of type 32011, since they employed living cultures as antigen in serum production and in agglutination tests.
Deacon (1952) carried out serological studies on 17 cultures of slow lactose fermenting Aerobacter cloacae including type 32011 and set up 12 O and 6 H antigens among them. Eveland & Faber (1953) also studied on 58 cultures of Paracolobactruin aerogenoides (Borman, Stuart & Wheeler, 1944) belonging to type 32011. According to them the 58 cultures were divided into 21 somatic and 22 flagellar groups. In the previous paper, Sakazaki & Namioka (1957) pointed out that Paracolobactrum aerogenoides cultures employed by Eveland & Faber included not only Hafnia cultures but also Cloaca and Citrobacter cultures. On the other hand, it is obvious from his description that several cultures of the 12 A. cloacae employed by Deacon belong to the Cloaca group, but do not to the Hafnia group. Therefore, the serological studies made in the past can afford little information for establishment of the systematic serology of the Hafnia group which would offer a contribution to the epidemiology of the group and assigning the taxonomical position in the family Enterobacteriaceae.
Many provious workers attached importance to the organisms as incitants of enteric disorder.
In spite of the consideration as enteric pathogen of the group, however, no sufficient evidence has been demonstrated to date.
The present studies were carried out to obtain sufficient information on the biochemical and serological characteristics of the Hafnia group and to investigate their ability producing enteritis.

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The toxin of Clostridium botulinum, which gives rise to food poisoning when ingested by man and animals, has been described as a true exotoxin. The toxin of Cl. botulinum type A was obtained in crystalline form (Abrams et al., 1946; Lamanna et al., 1946) and those of other types have been purified (Lamanna and Glassman, 1947; Duff et al., 1957; Cardella et al., 1958; Cardella et al., 1960; Sterne and Wentzel, 1950; Gordon et al., 1957) from cell free culture filtrate or whole culture. These reports also indicated that the toxins of Cl. botulinum types A, B, C, D, and E are simple protein. Accordingly the procedures employed in purifying the toxins were those that had been used in the isolation of proteins.
The recent knowledge on the toxin production by Cl. botulinum tells that the toxin is formed through activation of the atoxic precursor, which is synthesized in bacterial cells (Sakaguchi and Tohyama, 1955 a, b ; Boroff et al., 1952; Bonventre and Kempe, 1960) . Activation is accomplished by certain bacterial enzymes (Sakaguchi and Tohyama, 1955 a, b ; Dolman, 1957; Bonventre and Kempe, 1960) or trypsin (Duff et al., 1956) .
It has also been found that type E toxin has neutral or weakly basic property, whereas the precursor strongly acidic property, which was ascribed to the ribonucleic acid in the precursor molecules (Sakaguchi and Sakaguchi, 1959) .
The authors attempted to purify type E botulinal toxin according to the principle derived from the foregoing knowledge. In the attempt, young bacterial cells were used as the starting material instead of cell free filtrate or whole culture. The extract of the bacterial cells contained a large amount of ribonucleic acid and the precursor. The trypsinization of the extract released the toxin free from ribonucleic acid, which was precipitated with ammonium sulfate. It was found that the toxin purified from the bacterial cells by the method reported here has a potency higher than those described by other workers (cordon et al., 1957; Gerwing et al., 1961; Fiock et al., 1961) .

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Barksdale et al. (1960) described that the toxicity of the diphtheria “toxoid” preparation responsible for the Kyoto catastrophe in 1948 was equivalent to 10-20 MLD per cc for a guinea pig, and, based upon this result, made some considerations on the susceptibility of infants to diphtheria toxin. At the time of the accident, the present authors also performed ourselves detailed examinations on the toxicity of the same preparation and the toxicity was proved to be about 1/5 MLD per cc, a result quite different from that of Barksdale et al. Our own data had been presented only in Japanese (Ohtaguro, 1950), but its brief summary was published in this journal as an addendum of a paper by one of us (Kurokawa et al., 1959), which, however, Barksdale et al. did not refer to.
As we consider that the susceptibility of human beings to diphtheria toxin is much higher than that estimated by Barksdale et al. and that their description may give a fallacious interpretation to the reader about the pathogenicity of diphtheria and the significance of the detoxification test of diphtheria toxoid preparation for human use, it may be worth-while presenting our own data in detail.

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Whereas the epidemiologic study of parasitic helminth in Thailand have been reported by several authors, that of Laos and Cambodia is little known at present. We have an opportunity of visiting South Laos and Cambodia along Mekong River Basin in order to make a survey on schistosomiasis in 1960. During the staying period of one and a half months in that region, our survey was focused on three subjects; seeking a susceptible intermediate snail host of Schistosora japonicum, intradermal skin test of schistosomiasis on the inhabitants, and stool examination of the inhabitants.
As far as the schistosomiasis japonica is concerned, no trace of the existence of that disease was detected. This was already reported by us as an assignment report, WPRO 80, from the regional office of WHO in August, 1960. On the other hand it was revealed by the stool examination that a remarkably high incidence of intestinal helminth among the rural people was observed. So this is a report concerning mainly that incidence of intestinal helminth in the region of our short time examination.

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