Bent Elmann Creative Corner Natural Science Section XII (d)

Microbe attack has been obaserved to lead to a great increase in the white corpuscles of the blood, particularly in any disease-affected region. One purpose of these white cells would appear to be to resist microbic invasion. The cells actually attack and engulf the injurious germs. The white cells appear also to have an important part in restoring wounded tissue and no doubt they make good in some way the mormal wear-and-tear that goes on in the several organs of the body. This question, however, belongs to the more detailed department of physiology which needs the microscope for its study. Using this instrument, we perceive that every part and organ of our bodies is made up of minute individual organisms called cells. Every individual human being or animal begins life as the result of two microscopic cells fusing together to form a single cell. Thereafter growth results from cell multiplication. A cell multiplies by growing and then dividing in two. Thus one cell becomes two, two cells become four, four cells become eight and so on. The growth of the individual proceeds apace and eventually there are millions of cells to give him substance and form. The remarkable thing about growth is the way in which the cells become differentiated from one another, ultimately becoming of many different kinds. These specialist cells group together to form different kinds of tissue, such as muscle, bone, cartilage and so on. They combine to form organs such as stomach, liver, brain and so on. From the outset they appear to be motivated, knowing exactly how to become arranged to make a human being. The original cell from which the individual starts is provided jointly by mother and father, and simple as it appears to be when seen under a microscope, it is known to embody the form and character of the person destined to grow from it. All that we comprehend under the name of heredity is contained in this one cell that is first parent to all cells. Most living creatures, whether vegetable or animal, are equipped with special organs for generating the cells that are needed to make new individuals of their own kind. Some creatures are able to make both the cells whose fusion inaugurates a new life, but in man and other complex creatures the individuals are of two kinds distinguished as male and female. Each makes but one of the necessary cells, so that joint action between two individuals is needed to inaugurate a new life. The distinction of sex runs through almost the whole of Nature, so that even flowers and trees may be said to have maleness or femaleness. The expedients for bringing male and female cells together are extremely diverse, and in the vegetable kingdom insects may be called upon to carry the male cells (pollen) from flower to flower. Pollinated flowers produce fertile seeds that grow and form new plants under favourable conditions. No seeds can form in a flower that is deprived of pollen, because the unfertilised cells in its ovary come to nothing. In the kingdom of animals, birds, fishes and insects we find same principle obtaining. A cell from a female source must be merged with another from a male source in order to create a life-giving composite cell. In the higher animals and in human beings the encounter is arranged to occur in the person of female, who subsequently brings forth the new individual in a very immature form. Insects, fish, reptiles and birds generally produce eggs which require hatching, but the higher animals retain the new organism until it has a life of its own. The human baby cries directly it is born, and it must be given nourishment within a day or two of its first appearance. Nobody can explain with finality why the responsibility for multiplication in the vegetable and animal kingdom should have become a divided one calling for the joint action of the sexes, but the probability is that the arrangement was one of Nature`s tentatives that proved successful in the evolutionary scheme of things. If we could know anything about the first living things ever to divide this labour of reproducing themselves, we should probably discover that they had stolen a march on their competitors in the struggle for existence and became immensely successful at their rivals expense. We can only imagine how this might be, as we cannot pretend to give the actual facts. Among animals the sexes find pleasure in associating with one another, and in human beings the association is usually an associating for life. The mother is helped by the father in protect and nourish the offspring. The chance of survival in the struggle for existence is enormously increased where creatures develop moral qualities such as courage, loyalty and love of offspring, so that these qualities are as certainly the outcome of natural selection as is the great length of the giraffe`s neck. The vast reptiles of prehistoric times became extinct for a reason we cannot know with any assurance, but one guess as good as any other is that they failed to develop the requisite interest in their eggs or progeny. In an increasingly crowded world neglected eggs and defenceless infants would frequently become prey to a ravenous enemy; creatures had the alternative of adapting themselves to the new order of things or of becoming extinct. One successful adaptation was to lay more and more eggs; insects and fishes did that and so they survive to this day. A better adaptation, much less wasteful of life, was to submit to necessity and begin guarding the eggs. Birds followed this course of action. The great reptiles failed to adapt themselves either way and so they perished from the earth.