BASIC OF LIFE.

Waikato Times, Volume 103, Issue 17384, 21 April 1928, Page 10

BASIC OF LIFE.

A BIOLOGICAL STUDY. THE STORY OF PROTOPLASM. An interesting series of lectures on genetics, "The Breeding of Plants and Animals," was commenced in Wellington by Professor H. B. Kirk, of Victoria University College, under the auspices of the Workers' Educational Association. It was a matter of the commonest observation, said the lecturer, that living things, whether plants or animals, tend to be like their parents, but not exactly like them. The science of genetics sought to explain both the likeness and the unlikeness, to account for the rcssemblane between organisms and their parents, and to explain why the resemblances are not complete. The Law of Heredity.

The aim of genetics, said Professor Kirk, was not the study of evolution, although it was obvious that the key to the problem of evolution was to be found in genetics. Only by heritable changes proceeding progressively could there arise such differences as could lead to the infinite variety of species. The student of genetics might not greatly concern himself with tho broad problem of evolution, but his work must always tend to the understanding of that problem, and the evolutionist could never be indifferent to the discoveries of the geneticist.

The material with which heredity must deal, the essential living substance, was protoplasm. Although this substance was actually seen as early as 1755 and often observed after that date, and its behavious noted, it was not until 1835 that protoplasm was recognised to be different from other viscid substances, such as the white of cgs, and that its occurrence was always associated with living things. In that year Felix Dujardin, one of toe most efficient and yet modest workers in the whole realm of science, discovered in living cells a substance which on account of its softness he called sarcode, and he describes it as "this glutinous substance, transparent, insoluble in water, contracting into globular masses, sticking to the dissecting needles, allowing itself to be drawn out like mucus, found interposed between the other structural substances in all the lower animals." He had found the same substance present in the bodies of many other animals, such as worms and many of the one-celled organisms. In short, he examined no animals in which he did not find it and his tests showed that it differed greatly from other viscid substances often present, like albumen and mucus.

No Life Without It. This was the first recognition of a substance found to be constantly occurring in the bodies of animals, but the fact that it always exists in all living things and that no life can be without it was not yet recognised. That realisation came nearer in 18-iG as the result of the work of Hugo von Mohl, who demonstrated in plants the constant occurrence in the. living parts of a Arm, mucilaginous, and granular substance, for which the name of protoplasm was proposed. The complete recognition of its universality came in 1861, within the memory of men now living, when Max Schulze showed that the sarcode of Dujardin'and the protoplasm of von Mohl were one and the same thing, and protoplasm was now recognised as the physical basis of life and a substance without whose presence no animal or plant lives, nor any part of an animal or plant. The body of any organism except the very simplest contains many other substances than protoplasm, but these owe their presence to the activity of the protoplasm and may be said to be manufactured by it. It is a compound of great chemical complexity, and has what may be called a characteristic architecture, the complexity of which is not surprising when it is remembered that there is not only one kind of protoplasm, but several, all differing probably in chemical composition, and tiiat in most, if not all cases, two or more of these are mixed together. Only in one small group of organisms, known as slime fungi, docs this complex substance form an undivided mass of any size. In all others the body consists. of quite a small single mass or an aggregation of many such masses, each of which aggregations is called a cell. One very remarkable thing about protoplasm was all important to the student of genetics; it is never known to originate de novo, and it has never been manufactured. It grows and divides, and by division of existing protoplasm a new mass arises. The lecturer described the typical single-celled organism (amoeba) and its method of feeding and multiplication, and the essential difference between such creatures and those in which the cells aggregate into larger units and become complex organisms. The lecture, which was illustrated by a number of fine lantern slides, was followed by a keen discussion. Next week Professor Kirk will deal with •the material of "Heredity—Germ Cells Their Origin and Development."