August 24, 1882] 



NATURE 



409 



other delicate secreting membrane, such as, for example, the 

 mucous membrane of pulmonary air cells. 



8. The art orescent ramification of the blood-vessels accom- 

 pany the ducts in their development, and the reticulated 

 capillaries in which the bloodvessels terminate are extended 

 over all the closed elementary parts of the gland and supply them 

 with Mood. In the chick we may observe the simultaneous 

 development of the two systems ; in proportion as the develop- 

 ment of internal surface from a plain membrane to ca:cnm and 

 ramified ca?ca proceeds, the vascular layer of the originally simple 

 membrane is raised on the exterior of the efflorescence. 



9. The ramified canals and tubes, which when the structure is 

 simple, as in insects and Crustacea, and even in some glands of 

 the mammalia, lie free and unconnected, become more aggrega- 

 ted together, and acquire a common covering, in proportion as 

 their evolution is carried further ; and thus is produced a paren- 

 chyma or solid organ. 



10. The capillary blood-vessels are for the most part much 

 more minute than the smallest branches of the ducts of secreting 

 canals and their crecal extremities, even in the most complex 

 glandular organs. The elementary parts of glands, though 

 minute, are of such a size that the capillary blood-vessels lorm 

 around them a network which invests them. 



11. The formation of the glands in the embryo displays the 

 same progressive evolution from the simple to the complex state 

 as is observed in ascending the animal scale. The most perfect 

 and complex glands of the higher animals, when they first appear 

 tn the embryo of these animals, consist merely of the free efferent 

 ducts without any branches, and in that state exactly resemble 

 the secreting organs of the lower animals. The glands are 

 formed from the unbranched tubes by a kind of efflorescence or 

 ramification. 



12. The mode in which the extent of internal secreting surface 

 of a gland is realised is very various ; and no one kind of con- 

 formation is peculiar to any kind-of gland. Perfectly different 

 glands may have a similar elementary structure, a- is the else, for 

 instance, with the te-tes and the cortical sub-tance of the kidneys. 

 And similar glands have often a perfectly different structure in 

 different animals ; of which the lachrymal glands, examined in 

 the chelonia, bird-", and mammalia, afford an example. 



Johannes Midler, recognised thoroughly, as we have 'een, that 

 the character of a secretion cannot be deduced from the structure 

 of the organ which produces it. Was he able to throw any- 

 light npon the mystery which had baffled his predecessors and to 

 explain the cau^e of the specific endowments of the different 

 glandular organs ? Let us allow Muller to speak : — 



" The peculiarity of secretions does not depend on the internal 

 conformation of the glands ; for, as I have sufficiently demon- 

 strated, each -ecretion is in different animals the product of the 

 most various glandular structures, and very different fluids are 

 secreted by glands of similar organisation. The nature of the 

 secretion depends therefore solely on the peculiar vital properties 

 of the organic substance which forms the secreting canal-, and 

 which may remain the same, however different the conformation 

 of the secreting cavities may be ; while it may vary extremely 

 although the form of the canal or ducts remain the same." It 

 was the living lining substance of the gland which, according to 

 Joharmes Muller, formed the secretion, at the expense of mate- 

 rials which it obtained from the blood of contiguous capillaries. 

 This living substance lining the inner recesses of the glands had 

 not yet been differentiated into its constituent units, the secreting 

 cells, and therefore Midler's statement wanted a certain definite- 

 ne-s, though, so far as he went, he was perfectly accurate. 



The Researches of John Goodsir. 



The success with which that eminent pupil of Johannes 

 Midler, Theodore Schwann, had extended the generalisations of 

 Schleiden (on the part taken by the cell in the formation of 

 vegetable structures) to the elucidation of the animal tissues, had 

 given the greatest impulse to the study of animal histology, and 

 a large number of observers, especially in Germany and England, 

 were directing their attention to the discovery and study, in all 

 tissues and organs, of the all-important cells. 



Purkinjc had announced the hypothesis that the nucleated 

 epithelium wkich he discovered to line the gland ducts might 

 exercise secreting functions. Henle had described with great 

 minuteness the epithelium cells which line the ducts of the prin- 

 cipal glands and follicles, and which form the mo-t superficial 

 structures of mucous membrane, and Schwann had suggested 

 (bat this epithelium probably played a part in the act of 'secre- 



tion. It was, however, unquestionably the Scoitish anatomist, 

 John Goodsir, to whom was reserved the merit of establishing in 

 an indisputable manner the fact that the essential and ultimate 

 secreting structures in glands are the morphological units, the 

 gland cells. As Johannes Muller had examined the arrange- 

 ments and coarser structure of glands throughout the animal 

 kingdom, with the result of discovering the general plan of 

 gland-structure, and the analogies exi-ting between glands, how- 

 ever diverse, so John Goodsir passed under review the histologi- 

 cal characters of the cells of different glands in a large variety of 

 animals, vertebrate and invertebrate. His first results were pub- 

 lished in the "Transactions of the Royal Society of Edinburgh" 

 for the year 1S42 ; his more matured views were developed in a 

 paper entitled " On Secreting Structures," which formed one of 

 a collection of papers which saw the light in 1S45. As a result 

 of his survey Goodsir came to conclusions of which the most 

 important may be stated, almost in his own words, as follow s : — 



"The ultimate secreting structure is the primitive cell en- 

 dowed with a peculiar organic agency, according to the secretion 

 it is destined to produce. 1 shall henceforward name it the 

 primary secreting cell. 



" Each primary secreting cell is endowed with its own 

 peculiar property, according to the organ in which it is situated. 

 In the liver it secretes bile, in the mamma milk, &c. 



" The primary secreting cells of some glands have merely to 

 separate, from the nutritive medium, a greater or less number of 

 matters already existing in it. Other primary secreting cells are 

 endowed with the mire exalted property of elaborating, from 

 the nutritive medium, matters which do not exist in it. 



" The discovery of the secreting agency of the primitive cell 

 does not remove the principal my.-tery in which the function has 

 always been involved. One cell secretes bile, another milk ; yet 

 the one cell does not differ more in structure from the other than 

 the lining membrane of the duct of one gland from the lining 

 membrane of the duct of another. The general fact, however, 

 that the primitive cell is the ultimate secreting structure, is of 

 great value in physiological science, inasmuch as it connects 

 secretion with growth, as phenomena regulated by the same 

 iaws." 



Goodsir was unquestionably wrong in certain of his specula- 

 tions concerning secreting cells ; as, for instance, in attributing 

 at one time the chief part in the process of secretion to the cell 

 wall, at a later period ascribing the same function to the cell 

 nucleus. He certainly had not grasped the modern idea, which, 

 as I shall afterwards more particularly point out, considers the 

 act of secretion as one of the re-ults of the activity of the living 

 protoplasm of the cell. His assumption, too, that the secreting 

 cell invariably contains, preformed, the characteristic matters of 

 the secretion, is one which is by no means generally true. Never- 

 theless, it is impossible to study Goodsir's researches on the 

 secreting cell, without ascribing to him the merit of having been 

 the one who made the most important generali-ation, connecting 

 eell life with a definite organic function. 



I may be permitted, as it were parenthetically, to refer for a 

 moment to John Goodsir, with the veneration which is natural in 

 one who was his pupil. If it be true that the rapid march of 

 scientific discovery has caused us well-nigh to forget the great 

 debts which we owe to Johannes Muller, it is no less true that 

 John Goodsir's name has passed into premature and undeserved 

 oblivion. Goodsir's was a mind which in some respects, especi- 

 ally in its tastes, resembled that of Midler. He was a devoted 

 anatomist, and studied morphology in the fir-t instance for its 

 own sake, but also because of the light which it sheds on organic 

 function. He had a powerful intellect, an insatiable thirst for 

 knowdedge, a sympathy with all branches of inquiry which could 

 throw light upon the science to which he devoted his life, and a 

 devout and reverential spirit, which was not the less strong be- 

 cause it only rarely found audible, though then it was emphatic, 

 utterance. In the earlier part of his scientific career, numerals 

 papers, for the most part short, but characterised by remarkable 

 originality of observation and freshness of thought, seemed to 

 promise that Goodsir would be one of the most productive of 

 the workers of his time. A lingering illness which, without 

 altogether disabling him, enfeebled his physical powers, and cast 

 a gloom upon a life which had promised so much, almost put an 

 end to his career, in so far as the scientific world at large was 

 concerned, and henceforward he devoted his remaining energies 

 to studies of wdiich the results were for the most part not pub- 

 lished, but especially to the task of teaching. Goodsir was a 

 master who, if judged of by the low stand ird of fitness to in- 



