Growth and Development of Bengalee Girls: A Rare Book

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Studies on growth and development of children were persued on Indian population by the Indian Council of Medical Research in 1950s. This project did not cover some of the areas in the country. The largest area that remained uncovered included the States east of Uttar Pradesh. Since I set out to work, I began to nourish the faint hope that it might one day be possible to cover those states left out by the I. C- M. R. Eventually, my own study had to be restricted to a small corner and to specific details only. And this book is a record of some aspects of growth and development of Calcutta girls, whom I was finally able to study.

The data for this study were collected from January 1966 to January 1968, though the period of time for the entire study including preparations extended from July 1965 to July 1968. The University Grants Commission offered me a fellowship and contingency grant for these years. This study may be considered as a pilot one to satisfy the need for a height-weight-age standard of the Bengalee girls. It must be confessed that the girls below 8.5 years could not be included in it due to time restraint, and as such, the entire picture of the growth of the girls from birth to maturity is yet to be fulfilled.

I am most thankful to the Anthropological Survey of India for publishing this material. I had to omit some of the original discussions and figures comparing with other studies. This had to be done to facilitate the publication. To my beloved husband, Late Dr. D. K. Sen, former Director of the Anthropological Survey of India, I owe much more than I could mention. He encouraged me all along the period of the study. No less grateful I am to my subjects for their cooperation. Finally, I hope that the present growth study would help in stimulating many more studies in this line. This I shall consider for me, the greatest reward.

Introduction

Being born, growing to maturity, having progeny, then dying are the fundamental stages of life in plant, animal and mall alike. Of these stages ‘growth and development occupies a central place in the study of the mechanisms of evolutionary change, and central place also in the study of individual differences in the structure and function within the human species’ (Tanner, 1960). The period of growth, as Tanner (1962) states, occupies more than a quarter of a person’s lifetime. Searches for the patterns of changes in man’s body structure and functions, both external and internal, have been going on for the last two hundred years or so.

Distinguished workers in this field entertian different conceptions. Brody (1945) states, "Growth is biologic synthesis, production of new biochemical units. It is the aspect of development concerned with increase in living substance or protoplasm and includes one or all of these processes (1) cell multiplication (2) cell enlargement (3) incorporation of material from the environment." The third process in Brody’s definition means the inclusion of non-protoplas mic substances like fat, blood plasma, cartilage, etc., in the body; it is not a ‘true’ growth but a part of the growth process. Berrill (1955), while discussing about growth, says, "The size that any organism finally attains is the result of growth and the regulation of size is essentially a matter of rate and duration of growth." He continues: "Growth and therefore size regulation, is associated with all things living, from sub-microscopical molecular components of a cell to the giant organismal whales and redwoods... The basic phenomenon of growing to a limited size is a general characteristic of organisms and their parts." This is determined genetically in the species and in general not subject to experimental modification, other than a degree of stunting through some form of malnutrition. Berrill states that it is difficult to ascertain when growth ceases to be maximal.

Weiss (1949) says that ‘growth’ is not a scientific term; ‘it has come to connote all and any of these, reproduction, increase in dimensions, linear increase, gain in weight, gain in organic mass, cell multiplication, mitosis, cell migration, protein synthesis and perhaps more.

Needham (1933) subdivides growth into three headings or processes which are involved in it : (1) cell multiplication; (2) intussusception, or increase in size of cells ; and (3) accretion or increase in amount of non-living structural matter. According to him, growth is differentiated into (1) increase in number of kinds of cells; and (2) increase in morphological heterogeneity; and growth involves metabolism which he classifies as respiration or oxidation, fermentation or glycolysis, catabolism of protein, catabolism of fat and chemical activity, as pigment- formation, glycogen synthesis and so on.

According to Garn (1952), "The terms ‘growth’ and ‘development’ as used in physical growth studies refer to processes common to all living organisms, processes intimately linked in time but partially independent, unquestionably genetically determined, yet uniquely susceptible to environmental modification." Growth refers to the increment in the size of organs, increases in the thickness of tissues or changes of size of individuals as a whole.

With these definitions of growth in view, the differentiation of development from growth may be discussed. Development, according to Needham (1933), refers to the directive co-ordination of the diverse processes into an adult—into an ‘organized heterogeneity.

An "egg grows, differentiates and develops into chick, mouse, man or whale and goes through life according to its respective inherited pattern" (Brody, 1945). Brody includes growth in development, but some other authors, like Hammett (1936), define growth to include development. According to Hammett, growth is the co-ordinated expression of incremental and developmental factors and functions. Hammett defines growth as operational increase in weight. Growth may include abnormal or pathological cell division in any part of the body, for example the cancerous tissue, formation of a tumour, or a wart. It may also include normal cell divisions common to many parts of the animals like nails, hair, blood corpuscles, etc., without involving any development. This kind of growth by cell divisions may result in future destruction of the cells sooner or later as the hair-falls, nails shed oft or the skin of a snake is cast off. Growth may be positive or negative, according to Sir D’ Arcy Thompson (1942). A thing may grow larger or smaller and this may be applied to non—material things like tempera- true. While development results into a form of an object known by its magnitude, actual or relative, in various directions, "...growth involves the same concepts of magnitude and direction related to further concept or ‘dimension’ of time" (Thompson, 1942). The fullfledged developed form of an organism is determined by the rate of growth in various directions.

The rate of growth differs from one part of the body to another from one individual to an- other and from one species to another. Thompson (1942) defines this rate as "when in a two- dimensional diagram we represent a magnitude (for instance, length) in relation to time (or ‘plot’ length against time, as the phrase is), we get that kind of vector diagram which is known as a ‘curve of growth’. We see the phenomenon which we are studying is a velocity (whose dimensions" are space/time or L/T), and this phenomenon we shall speak of simply as rate of growth." As this rate of growth differs from population to population, studies on growth in plant, animal and men are incessantly being pursued.

As early as the 5th Century B.C. a Greek physician developed a method for the study of growth which is still being employed. A hen was set upon a number of eggs and on each day an egg was taken out and opened to find the changes and developments that took place for the formation of a full—fledged chicken in 21 days. The study on the growth of the embryos of lower animals has advanced considerably. The lower animals and birds are easier to study, but the embryos of the higher animals and man are not so easy of access. However, cows, pigs, cats and monkeys have been studied almost exhaustively (Lewis and Gregory, 1929; Gregory, 1930; Squier, 1932; Lewis and Wright, 1935; Ragsdale, 1934; Whetham, 1934-35) in their embryo- logical stages. Professor Schultz (1925) has made valuable contribution on the foetal growth of primates and man.

Growth of animals, after they are born, has been more extensively and intensively studied many authors. To name a few of them: Allen (1918), Hoskins and Hoskins (1917) on Osborn and Mendel (1926) on rats, Whetham (1934-35) on pigs; Ragsdale (1934) on cattle; Schultz (1940) and Yerkes (1943) on anthropoid apes. Schultz (1960) has shown the similarity in the growth of primates and man.

As early as 1750 the cross—sectional or mass method of growth study of man began with the work of Roederner in 1753 followed by Dietz in 1757, and Joseph Clarke in 1787. Their work was mainly on the weight and physical proportions of new-born babies. Detailed study of development at later ages did not start till the early part of the nineteenth century.

The first longitudinal or seriatim study of growth in man was made during the years from 1759 to 1777 by Count Philibert Guenean de Montbeillard. Montbeillard measured his son mostly bi-annually from birth to 18 years of age and handed over his data to his friend Buffon who published those in the 4th volume of his book Historie Naturelle as a supplement in 1776. Others started working on the same line of study on growth long after Buffon’s publication, and in 1855 Quetelet, in 1890 Wiener, and in 1915 Guttman published their classic work. Other publications on growth study of children in the early part of the present century include the works of Variot (1908), Freund: 1909), Schloss (1911), Aron (1911), Boas (1912), Baldwin 1921), and Goldstein (1922).

Though in recent years more stress is being given to the longitudinal study of growth (measuring the same child repeatedly all through his growing period), the importance of cross- sectional study cannot be ignored. In the cross-sectional study a number of children of different ages are measured only once, so that the means of measurements at different age levels may be accepted as representative for that particular population (if it is a homogeneous one). The elementary concept of the cross-sectional study was perceived as early as 1694 by Borelli—a Belgian scientist— who measured some Belgians from one year through eighty years of age, The cross—sectional method of study is still being continued all over the world. The two great advantages of cross-sectional study are that it is cheaper and is less time-consuming. Tanner 1962) mentions the other advantages of this kind of studies 2 "They tell us most of what we want to know about the distance curve of growth ; that is about height attained at a particular age. Clinical standards for height attained by healthy children at various ages can be constructed from purely cross-sectional data." The mean ages of menarche, appearance of secondary sexual characters, emergence of teeth both milk and permanent sets, menopause, etc., for a population can be found out more conveniently by cross-sectional studies. Together with the mean, the standard deviation and standard error give a picture of the achievements for the population as a whole. Israelsohn (1960)) is of opinion that ‘cross-sectional methods are adequate for studying distributions of various measurements in different individuals at different ages and for constructing standards of growth attained, e.g., height and weight standards. In these circumstances the relative case and rapidity with which results may be obtained from a large number of cases make the cross-sectional method preferable to the longitudinal one the longitudinal method, apart from being expensive and time-consuming, involves the co-operation of the subjects and their guardians which are absolutely indispensable. Many a longitudinal study for this reason has failed to be a pure one. Often they are mixed longitudinal, i.e., partly cross—sectional, as some subjects drop off and some new ones are added. Even the pure longitudinal data are treated as cross-sectional to arrive at the average velocities, and as Israelsohn (1960) says, they are poor representation of the population. This drawback of the longitudinal study was also realised by Boas (1892). Bryan and Greenberg (1952) have shown how important the cross-sectional study is for statistical method in estimating the importance of socio-economic background in growth.