Morning journal and courier., 1881-02-16
shenie1d scientlfic school.

ErofeS5or Cn1ttenden, or the D. D. D., lu- terested large audience at North Sheffield Hall last evening, delivering the second in the course of lectures to mechanics. Many learned gentlemen and many young men pur- suing course of instruction in one or other of the departments of Yale were included in the assembly, and sprinkling of ladies. Despite the technical difficulties of the sub- ject, the lecture was highly interesting and engaged close attention. It was accompanied by illustrations thrown upon the screen, Professor Brewer assisting in the mechanical naOdUs OpeTG7adS at the opposite side of the hall. Following are extracts
 The nature of life is @ question which has occupied the attention of thoughtful men for many ages in fact, it is probably one of the first problems which the old philosophers at- tempted to solve. In looking back over the record of physiological progress, it is not strange then that we find numerous efforts have been made by representative men of different centuries to define life. Thus Aris- totle 32O B. o., with sagacity far in advance of his time, left on record the following def- milton: 'Life is the assemblage of the opera tions of nutritious growth and of destruc- tion''
 Bichart, in common with other men of his age, impressed with the idea that life is con- tinual struggle with death, defined life as the 'ssum total of the functions which resist death"
 Beclard, a celebrated French philosopher, has defined life as Organization in action, :" while Herb ert Spencer asserts that life is ''the continual adaptation of internal relations with external relations" meaning thereby, it is to be presumed, that life is the result of 8 continual intercourse between matter which is within the body and that which is without.
 All of these definitions are however, when subjected to careful scrutiny, vague and un- satisfactory they either express too much or too little. If concise they are deficient in completeness of statement, if voluminous they express more than accurate knowledge justifes.
 Beclard' s statement that life is organization or action, is certainly very expressive, but like other definitions on this subject, it pre- supposes some organized structure, the ex- istenee of which is taken for granted. Thus while various theories have been offered from time to time two fundamentally opposite doc trines have been and are maintained as to the nature of life, and under one or the other of these, all the views on this subject hitherto promulgated must be arranged. According to one school life is the product of organiza- tion.
 Thus Dr. Beale, of England, as champion of this latter class of thinkers, asserts that zE tion," and defines life as ''power, force or property of peculiar kind, temporarily in-
 1uencing matter and it's ordinary forces, but entirely different from and in no way related with any of these'' While certain class of thinkers have thus supposed that life is an in dependent principle, capable of being added to or removed from matter, and that all the phenomena of life resulted from the action of an immaterial or conscious existence or prin- ciple, acting directly or indirectly on the mechanism of the body, 8 second class have imagined that vital actions come under the same laws as physical actions, and that vital actions are directly affected by external con- ditions
 From the point of view of the physiologist or chemist, who deals with direct observa- tions of normal phenomena, or phenomena as modified by experiment, 1t is not necessa- " to assume the operations of living pr1n- ciple independent of matter, although upon evidence of an entirely different kind he may be convinced of the existence of such a principle. It is the duty of the physiologi- cal chemist to investigate the conditions un- der which vital phenomena occur, and though such studies have and still do throw considerable light uron our knowledge of the processes of life, as well as upon the nature of the force which guides and controls these processes, any definitions attempting to de-
 fine life itself are of but little value inas- much as in the present state of science our knowledge of vital processes is somewhat de- ficient and as it is extremely probable that the molecular changes which we associate with vital phenomena may never be thor oughly understood.
 At the present day vital power or the so- called vital force, instead Of being looked upon as altogether peculiar, is gradually more and more so recognized as result of physical forces which, in the words of Dr. Carpenter, have been transformed by passing through the organism If, however, that which has been termed vital should prove in the future to be simply a condition of matter it will be none the less mysterious. The intimate na- ture of the phenomena of gravity, chemical activity, magnetism and electricity is just as obscure as that of vital actions, or in other words the contraction of a protoplasmic element of the body, the contraction of muscular tissue, the growth of 8 cell or the connection between change in a portion of the brain substance with sensation or an emotion, are processes no more inexpicable than the influence of a current of electricity on a magnetic needle or the falling of a heavy object to the earth.
 What now is there so very peculiar in iv- ing beings that renders it impossible for us to define life ? and the only answer we can give to this question is-life itseH. Yes, life is peculiar, indefnable, it's attributes are won derful and it's origin uncertain.
 Dat let us glance for a few minutes at 8 few of the characteristic of living beings as dis tinguished from unorganized matter in order that we may better comprehend all that the word life implies. And first we notice that living bodies are organized, that is to say they are composed of dissimilar or distinct parts arranged in 8 certain order, each part performing @ definite office in connection with the maintenance of the life of the whole Again the external form of living beings is in accord with certain neurological type At the very commencement of existence the typical form is nearly spherical but afterward in the process of growth form is developed peculiar to the species. This spherical form, which is so characteristic of the organism at the commencement of life, is not. be--sver, lost during the development @<tne specltlc form, but is seen in tke maturing as well as in the fully da-[oped body, contained in all the tissuos and fluids which compose the or ganlsm.
 This spherical body is called cell, and it may be regarded as the most simple, the most common and the earliest form of or ganism met with. Now if we examine the animal series from the more simple to the most complex, the organization is seen to be- come more and more intricate by insensible transitions. First of all we find unicellular organisms, consisting of simple mass of jelly-like matter called protoplasm, of which the microscope amoebra is good example. This simple drop of jelly, resembling the white corpuscles of human blood, is true animal in spite of it's size, for if watched un- der the microscope sufficiently long it is seen to contract it's substance into different shapes and forms, rolling along like an irregularly shaped and microscopic ball of jelly, until coming in contact with some particles of food it's motion is stopped; but only for a time for.this living drop of matter, with all the eagerness of hungfy man, wraps itself about the foreign matter, and in the, cavern ous stomach thus formed digests and absorbs such particles as are suitable, and then rolls away from the undigested residue. Thus this simple animal, endowed with many of the properties of higher beings, lives, moves, eats, grows, and finally dies, having, been nothing more than small, even microscopic | particle of protoplasm.
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