y'luj^. 20, 1874 



NA TURE 



327 



volcanoes before the Secondary or Mesozoic period. The Silu- 

 rian volcanic districts of North Wales and of the west of Ire- 

 land, and the Carboniferous volcanic districts of Limerick and 

 Scotland, bear witness against the soundness of such a view. 

 This statement, however, does not necessarily invalidate the 

 general views of the author ; and I cannot but think that the 

 jiublication of Mr. Mallet's paper has enabled us to take a vei'y 

 long stride in the direction of a true theory of volcanic energy. 



SECTION D 



Biology 



OrENiNG Address by Prof. Peter Redfern, M.D., 



President 



I con'sented to allow myself to be nominated President ot 

 this Section in compliance with the kindly-expressed wishes of 

 scientific friends, notwithstanding that I felt that the duties of the 

 Chair would have been more fitly discharged by many who have 

 attended the meetings of the Association more regularly and 

 laboured to promote its objects more continuously than I have 

 been able to do. 



Portunately the increasing importance and the vast extent of 

 the subjects comprised under the head of Biology have led to a 

 division of the business of this Section into the separate depart- 

 ments of Anatomy and Physiology, Botany and Zoology, and 

 Anthropology ; and it is a great relief to me that the departments 

 of Botany and Zoology, and of Anthropology, respectively, will 

 be presided over by gentlemen of the highest eminence in those 

 subjects, and that Anatomy and Physiology, in which I am more 

 immediately interested, will alone come under my direct super- 

 vision. It has occurred to me that, in attempting to give a 

 stronger impulse and a more systematic direction to scientific 

 inquiry, the time ordinarily devoted to an introductory address 

 could not be moie profitably occupied than by bringing into as 

 great prominence as possible some of the great revolutions in our 

 knowledge of Anatomy and Physiology which have taken place 

 in my own time and under my own immediate observation. 



I remember, as if it were yesterday, the elucidation in the 

 Museum of the Royal College of Surgeons of Edinburgh, of the 

 newly discovered cell-theory by the late distinguished Professor 

 of Anatomy in Edinburgh, John Goodsir — his account of the 

 production of ulceration by cell-growth, of the characters of the 

 corpuscles of bone, of the structure of lymphatic glands, and of 

 the germinal centres of basement membranes as they were then 

 understood. This w.as the time when the teaching of Histology 

 was first established in Great Britain. Two students, of whom I 

 was one, formed the first class under the most enthusiastic of 

 teachers, my old friend, Dr. Hughes Bennett. The University 

 of ICdinburgh has just passed through what was probably the 

 most brilliant period in its history. The race of the last of the 

 Munris was well-nigh run ; the great discoverer of the diflerence 

 in the motor and sensory nerves. Sir Charles Bell, was still living ; 

 the aristocracy of Scotland had only just ceased to crowd the 

 classroom and witness the brilliant and successful experiments 

 of Dr. Hope. The day of Cullen, of Home, and Duncan, and 

 Macintosh was over; but there still remained in the University 

 the most loved and revered of teachers, the benevolent Dr. 

 Alison, Sir Robert Christison, Sir George Ballinghall, and Mr. 

 Syme, Dr. Abercrombie still practising his profession in the 

 city. 



At this period the great discoveries of Sclileiden and Schwann 

 seemed likely to upset all that had previously constituted Physi- 

 ology. The idea that all tissues were either composed of cells 

 or had been formed of cells — that nucleated cells elaborated all 

 the secretions and formed the excretions — that their energy lay 

 at the very root of the formation, the reproduction, and the 

 function of every tissue and organ, was a revelation of such 

 astounding simplicity as might well upset men's minds and pre- 

 vent their seeing beyond. 



No one, who did not live through that time, will, I believe, 

 ever realise the eagerness and anxiety with which every new 

 statement of the aclioii of cells was received and added to the 

 previous knowledge of their amazing power — or, on the other 

 hand, be able to judge of the feeling, half akin to disappointment, 

 which was experienced as each succeeding attack was made on 

 this charming theory, showing it to be really human, very human 

 indeed. 



Cells were then understood to constitute the mass of all organs 

 (the liver, spleen, kidney, and brain), and to be the main agents 

 in the discharge of their functions— to e.xist and grow upon the 



definite membranous walls of the glandular vesicles and ducts— 

 10 be fed by blood brought to the attached surface of membranes 

 which seemed almost everywhere to form an absolute separation 

 of the cellular part (the potential gland) from the non-essential 

 blood and lymph-vessels, the nerves, and framework of the 

 organ. It seemed almost a pity that these little microscopic 

 deities should be hampered by the necessities of their own exist- 

 ence, that they should need such base things as blood-vessels, 

 nerves, and packing materials. Now how strangely are matters 

 changed ! What if it should turn out that these apparently in- 

 dependent little beings are not independent at all —that they are 

 only the dilated ending of nerves ? To this subject I shall refer 

 again by and by. 



This great cell-theory has now given place to what I think is 

 certain knowledge, that living matter may move, perform all the 

 functions of assimilation and nutrition, and reproduce its like 

 without having any of the essential characters of a cell. A living 

 mass of protoplasm may change its shape, alter its position, feed 

 and nourish itself, and form other matter having the same pro- 

 perties as it, has, and yet be peifectly devoid of any structure 

 recognisable by the highest powers of the microscope. 



Mr. Lister showed that the contraction of pigment- cells in the 

 skin changes the position of the pigment-granules, driving them 

 alternately into the processes and the body of the cell. Kiihne, 

 Golubew, and Strieker observed ch.anges of form in amoebce 

 (white blood-corpuscles and embryonal capillaries, respectively) 

 after the application of electrical stimuli; and Briicke observed 

 contraction in the pigment-cells of the skin of the chameleon after 

 excitation of the sensory nerves ; whilst Kiihne noticed contrac- 

 tion in corneal cells after excitation of the corneal nerves. 



Thus obvious movements in fixed cells or masses of protoplasm 

 are proved to result from the operation of various stimuli, in- 

 cluding nervous stimuli. 



But all cells are not fixed. The blood-cell?, fixed, as cells of 

 organs, at .an early period, become free in the blood-lluid and 

 are moved along by the forces which circulate it until a second 

 time they enter into the composition of the solid tissues by 

 penetrating the w.alls of the blood-vessels and moving along the 

 substance of the tissues for purposes which are not yet wholly 

 explicable. 



What naturalist will not at once suggest how frequently this 

 process of alternate fixation and movement of animal forms 

 occurs low down in the scale? and yet how startling is it in 

 man ! how impossible to reconcile with our former ideas of the 

 existence of membranous coverings, of cells, surfaces, and of 

 gland-ducts I But, with or without explanation, the facts must 

 be recognised ; the floating blood-cells are really the very cells 

 which once formed the substance of the lymphatic glands, the 

 spleens, and other organs ; and they do, in fact, move through the 

 walls of the blood-passages, and wander about freely in what we 

 call solid tissues. 



Our knowledge of this circulating fluid has marvellously in- 

 creased. The dur.ation of the life of any of its particles is but 

 short ; they die and their places aie occupied by others, as was 

 the case with our forefather.', and will be the case with ourselves. 

 It is now a matter of obserration, which commenced with Hirt 

 of Zittau, that after every meal an amazing number of white 

 corpuscles are added to the blood : breakfast doubles their pro- 

 portion to the coloured corpuscles in half an hour ; supper in- 

 creases their proportion three times ; and dinner makes it four 

 times as great. They come from such solid glands as the spleen. 

 In the blood going to Ihe spleen, their proportion is one to two 

 thousand two hundred and sixty ; in that returning from the 

 spleen it is one to sixty. Every organ and every tissue changes 

 this fluid ; and, to my mind, perhaps the most stupendous 

 miracle of organisation is the steady maintenance of but slightly 

 variable charjcters in the living and moving blood which is 

 every moment undergoing changes of different kinds as it circu- 

 lates through each tissue and organ in the body. 



Yet with all this change there is an inv.ariahle tr.ansmission of 

 the parental characters by cuatinual descent from particle to 

 particle as each takes the place of a former one ; and thu; each 

 organ continues to discharge the same function from year to 

 year. Animals of the same kind retain the old number of organs 

 the same shape uf body, and s'inilar modes of life. There is nu 

 sign of commencing life, no coining of new vital power, no pro- 

 duction of living out of dead matter. The original life extends 

 its limits ; it operates in a more extended sphere ; but it is the 

 same life, it operates in the same way, it jiever fails to be recog- 

 nisable in the individual by the same characters as it had 

 when it w as first known. Whatever other functions it disch.irges, 



