It is apparent that no changes occur in its total mass, total weight, and in total volume, even when the shape of a clod of clay of a definite mass is modified by any methods. Some children think, however, that some of the total mass, the total weight and the total volume of this clay change during the procedure of modification in its shape. The authors investigated, therefore, at about what age the children get the right ideas concerning the conservations of mass, weight and of volume of a matter, which are independent of the change in its shape. The number of the school children on whom the investigations were made was 74 (the 1st grade…24, the 2nd grade…25, the 3rd grade…25). On the other hand, it was necessary for the authors to investigate whether the concept of volume has already been fixed in the minds of children before starting their investigations concerning the degree of fixation of the conservation of volume in the children. In order to make these investigations, some special tools (such as clay balls, rods of brass and styrene balls) were used, and the children were questioned whether the surface-level of the matter in a beaker (water, powder or soil) moves upward or downward when one of the above described tools was completely immersed in it. During the processes of the investigations, the followings became obvious. (1) In the course of growth of children, the concept of conservation of mass, that of conservation of weight, that of volume and that of conservation of volume are settled in the minds of children in their order. (2) The concept of conservation of mass is of very vague character in the minds of the very young children. But, as the concept of conservation of weight or the concept of conservation of volume is fixed, the original concept of conservation of mass is strengthened with them and comes to possess the very firm scientific character. This second conclusion teaches us that in the course of education, it is important for the teachers to suggest their children how the law (or knowledge) which has just been discovered in the present classroom can be used for re-constracting some old laws (or knowledges) which were already caught in the past or for detecting any new laws (or knowledges) in the future. The number of the children in each of the definite degrees of growth of minds (putting the number of the whole children investigated as 100) is shown in Tables 11~13 which indicate that the four concepts investigated become settled earlier in boys' minds than in girls' minds.

The authors attempted to examine the pupils of a primary school in natural science. In this examination, they paid special attention to testing their ability of scientific thinking and extracted the factors constituting the structure of science from the above result. This is the consequence which could be gained through these factor analysis. (1) Four are extracted as factors of ability in scientific thinking, that is, Ability of Inductive Thinking (a), Ability of Deductive Thinking (b), Ability of Understanding (c), and Ability of Recognizing Space (d). (2) By comparing these results with the factors of ability in scientific thinking of the pupils of a junior high school (this report III), they come to the conclusion that the factor a, b and c are common factors in both schools. (3) By comparing these results with the factor analysis of intelligence by L. L. Thurstone, they find that the factors of ability of scientific thinking are correspond to the many intelligence factors. (4) Then, inquiring into the relation of factors of Inductive and Deductive thinking, they come to the conclusion that these factors are independent but are connected intimately in practical thinking.

The Author had already published that the scientific consideration composed of 13 constructional elements, and each element has peculier step of development, and then showed them from the 1st year of primary school to the 3rd year of lower secondary school, and related them to the steps of the growth that Jean Piaget had studied. But when we had been proceeding our research, we felt the need of the research for the steps of infant. Then in this essay we tried to show the relation for development between each constractional element, and J. Piaget's research. But this research is only beginning and needs the correction in future. It is reliable that this results supplr contributions to the science teaching in infant education or in special education at least.

The active bodies and the resistance cysts of Blepharisma undulans japonicus Suzuki, 1954〔B. japonicum Suzuki (Bhandary, A. V. 1962), Plankton, Ciliata〕were cultured under the definite condition, and the following valuable results in science education 〔(1), (2)〕wereobtained. (1) As the teaching materials, the active bodies and the resistance cysts of the AR strain of this subspecies were more suitable than those of Paramecium etc., due to the following points of (a) and (b). (a) The active bodies are easily cultivable like those of Paramecium etc. by the rice straw infusion (Fig. 1, Fig. 2, Table 1). They are beautifully reddish in color, very large in size (about 650μ,～730μ, in length, about 230μ,～300μ, in width), and seen by the naked eyes. They move forward, smoothly and very slowly (3sec.～8sec./mm.). Therefore, an active body in the culture medium is easily taken by a pipette, and its descendants are easily reproduced numerously by the repeated binary divisions (Table 2). Moreover, the resistance cysts are brownish black in color, roundish or ovoid (about 90μ,～170μ, in long dia., about 80μ,～140μ, in short dia.), and able to be kept living in the culture medium for a long period and germinated at need (Table 3, Fig. 3). (b) Such a curriculum as the individuals of this strain are used as the teaching materials instead of Paramecium etc., was applied to the pupils of the kindergartens, elementary schools, junior high schools and senior high schools. It was confirmed that the educational value of such a curriculum was higher than that of the traditional one which used Paramecium etc., (refer to 〔5〕）．(2) The following important points (a)～(g) which have not been studied yet were investigated, by cultivating the following (1)～(5) strains of this subspecies under the definite condition (the rice straw infusion, 25°±1°C, pH 7.0±0.2, etc,) ; (1) the red active bodies of the AR strain, (2) the white active bodies of the AW strain which are the variations of the red active bodies of the AR strain without passing through the stage of the resistance cyst, (3) the red active bodies of the BR strain, (4) those of the CR strain and (5) those of the DR strain. (a) The topographical habitat of this sub species and the average chemical composition of the water in the habitat (Fig. 1, Photo graph 9, Table 1). (b) The biotope of the individuals of the AR strain concerning a change of temperature or pH of the culture medium, and especially the range of the formation of the resistance cysts of this strain (Fig. 2). (c) The days required for the excystments of the resistance cysts of the AR strain increase according as the days after their formations increase. The ratios of their excystments are also researched (Table 3). (d) The active bodies of both the AR strain and the AW strain possess negative geotaxis, which is almost of the same grade in both strains (Table 4). (e) The active bodies of both the AR strain and the AW strain possess negative phototaxis, which is almost of the same grade in both strains (Table 5). (f) The active bodies of both the AR strain and the AW strain possess negative electrotaxis, which is a little more con spicuous in the latter than in the former (Table 6). (g) The mating experiments among four strains, i. e., AR, BR, CR, and DR strains (Table 7). On the basis of these points (a)～(g), we conclude that the exploitation of this sub species as the teaching materials is very effective in science education.

In recent years, molecular biology has been making great advances and influenced on the biologicical curricula of senior high school. The writer examined several Japanese and foreign text books for the purpose of studying these influences. These text books used for the examination were BSCS Text Books containing Blue, Yellow, Green Version and each Revised Edition, Nuffield Biology Text v, ОБЩАЯ БИОЛОГИЯ of USSR and Japanese text books published at present. There were some differences in the curriculum between these foreign text books and Japanese. The foreign text books were all composed on the basis of innovation in the curriculum of the science education. On the contrary, in the case of Japan the biological curriculum enforced since the year of 1961 remained invariably and the teaching material of molecular biology in troduced, when the textbooks were improved under the educational authorities. So in the foreign cases the place of this material were decided with the view of theoretical curriculum in which the modernization of science education performed. In most Japanese textbooks were inserted - 51 -the explanation of DNA model and its pattern of self-duplication as the background of genetic phenomena and some textbooks added the description of instruction for protein which composed all enzymes and elements of protoplasmic structures. In these books, it might be thought that the concept of DNA and RNA were not helpful for the understandings of other life-phenome nas sufficiently. Other textbooks did not illustrate this material and a few books tried to construct new curricula, but they were like to BSCS Blue version system. In the viewpoint of molecular biological theory there can be two locations in the arrangement of all materials that constructs high school biology. One is in the study of molecular level. This means that DNA material serves the building of basic concept on the life phenomena and the understanding of background for cell division. This location also means that the study of nucleic acid is carried in the early stages of whole learning systems in general. Other is in the study of inheritance, and it may be useful for the understanding the essence of genetic phenomena. For example, many students may be able to know that the thought of DNA model must be concluded through the process of inquiry to Menderism as an inevitable consequence and the partial change of DNA brings about the effect of mutation. As described here, main Japanese text books put the explanation of DNA and RNA structures on the part of chemical compounds contained in living bodies and these functions on the end of genetic learnings. Such separated location may lead the students to the study only for getting the knowledge of nucleic acids. From the standpoint of teaching method, the study of nucleic acids shows the pattern investigated by using model which gives the concept of cotinuity to the students. Moreover, main foreign examples evaluated as the innovated curriculum attach importance to the higher level of organisms such as the world biome or ecological materials as accompanied with the increasing of micro levels or molecular biological materials. It means that the study of biology contains not only the realizing mechanisms but also the recognizing the situation of living things in the natural world. The writer concluds that the teaching material of molecular biology should be reconstructed in the whole series of innovated curriculum at the theoretical standpoint and its teaching method should be also reexamined.