116 UEPORT — 1871. 



the danger of confined views on the part of those whose attention, from necessity 

 or taste,' is too exclusively directed to the details of one department, or even, as 

 often happens, to a subdivision of it. It would seem, indeed, aa if our predecessors 

 in the last generation possessed this superior advantage in the then existing nar- 

 rower boundaries of knowledge, that it was possible for them to overtake the con- 

 templation of a wider field, and to follow out researches in a gi-eater number of the 

 sciences. To such combination of varied knowledge, united with their ti-anscen- 

 dent powers of sound generalization and accurate observation, must be ascribed 

 the widespread and enduring influence of the works of such men as Haller, 

 Linnseus, Cuvier, Von Baer, and Johannes Miiller. There are doubtless brilliant 

 instances in our own time of men endowed with similar powers ; but the diffi- 

 culty of bringing these powers into effectual operation in a wide ran^e is 

 now so gi'eat, that, while the amoimt of research m special biological subjects 

 is enormous, it must be reserved for comparatively few to be the authors of great 

 systems, or of enduring broad and general views which embrace the whole range 

 of biological science. It is incumbent, therefore, on all those who are desirous of 

 promoting the advance of biological knowledge to combat the confined views which 

 are apt to be engendered by the too gi-eat restriction of study to one department. 

 However much subdivision of labour may now be necessary in the original investi- 

 gation and elaboration of new facts in our science (and the necessity for such sub- 

 division will necessarily increase as knowledge extends), there must be secured at 

 first, by a wider study of the general principles and some of the details of collateral 

 branches of knowledge, that power of justly comparing and correlating facts 

 which will mature the judgment and exclude partial views. To refer only to one 

 bright example, I might say that it can scarcely be doubted that it is the unequalled 

 variety and extent of knowledge, combined with the faculty of bringing the most 

 varied facts together in new combination, which has enabled Dr. Darwin (what- 

 ever may be thought otherwise of his system) to give the greatest impulse which 

 has been felt in our own times to the progi-ess of biological views and thought ; 

 and it is most satisfactory to observe the effect which this influence is already 

 producing on the scientific mind of this country, in opposing the tendency per- 

 ceptible in recent times to the too restricted study of special departments of natural 

 history. I need scarcely remind you that for the proper investigation and judg- 

 ment of problems in physiology, a full knowledge of anatomy in general, and much 

 of comparative anatomy, of histology and embiyology, of organic chemistiy and of 

 physics, is indispensable as a preliminaiy to all successful physiological observation 

 and experiment. The anatomist, again, who would profess to describe rationally 

 and correctly the structure of the human body, must have acquired a knowledge of 

 the principles of morphology derived from the study of comparative anatomj' and 

 development, and he must have mastered the intricacies of histological research. 

 The comparative anatomist must be an accomplished embryologist in the whole 

 range of the animal kingdom, or in any single division of it which he professes to 

 cultivate. The zoologist and the botanist must equally found their descriptions and 

 63'stematic distinctions on morphological, histological, and embryological data. Aaid 

 thus the whole of these departments of biological science are so interwoven and 

 imited that the scientific investigation of no one can now be regarded as altogether 

 separate from that of the others. It has been the work of the last forty years to 

 bring that intimate connexion of the biological sciences more and more fully into 

 prominent view, and to infuse its spirit into all scientific investigation. But while 

 in all the departments of biology prodigious advances have been made, there are 

 two more especially which merit particular mention as having almost taken their 

 origin within the period I now refer to, as having made the most rapid progress in 

 themselves, and as having influenced most powerfully and widely the progi-ess of 

 discovery, and the views of biologists in other departments — I mean Histology and 

 Embryology. 



I need scarcely remind those present that it was only within a few years before the 

 foundation of the British Association that the suggestions of Lister in regard to 

 the construction of achromatic lenses brought the compound microscope into such 

 a state of improvement as caused it to be restored, as I might say, to the place 

 which the more imperfect instrument had lost in the previous century. The re- 



