324 Transactions of the [Sess. 



and separate lines of inquiry being pursued, so that if we again 

 borrow an illustration from biology, — just as plants or animals 

 may, when looked at as a whole, be likened to a tree having a 

 common root in the soil, and a common trunk rising into the air from 

 which many specialised branches are given off, so the Hookes, 

 Leeuwenhoeks, and Malpighis may be venerated as the great 

 trunks from whom many have branched off, each to pursue his 

 special investigations. How numerous now these branches have 

 become ! 



From the year 1800 onwards, many illustrious names cluster 

 round our instrument as helping to perfect it. Chief among these 

 may be noted WoUaston, Frauenhofer, Biot, Amici, Chevalier, 

 Brewster, Airy, Ross, Lister, and Coddington. But the discoveries 

 made within the same period have been, I may say, unexampled in 

 the history of any science. MuUer, Ehrenberg (whose ' Infusoria ' 

 will ever be a landmark in microscopy), Vaucher, Brown, and Von 

 Mohl, have laid succeeding generations under a permanent debt of 

 gratitude ; but with the appearance, in 1837, of Schleiden's classic 

 paper on cell-structure, may be said to have commenced the dawn 

 of Botany as a science. When he enunciated the law that all 

 plants are composed of one or more little vesicles or cells, of 

 definite structure and history, and that every cell springs from a 

 pre-existing cell, a broad and solid basis was laid for a mighty 

 superstructure of scientific histology. Since his day botanists 

 have been largely concerned in developing and amplifying his 

 generalisations. 



Considering the greater diflBculty in examining animal tissues, 

 it need scarcely be wondered that several years elapsed ere 

 Schwann propounded for the animal kingdom a law identical with 

 that of Schleiden's for the vegetable. And here again the great 

 mass of investigation of recent times is simply an explication of 

 the arrangement, work, nature, and history of animal cells in health 

 and disease. Edinburgh can hold it as a sacred tradition that the 

 man of her own intellectual upbringing, the late Professor Goodsir, 

 first proved clearly that all disease is due to alterations in the 

 normal condition of cell life. 



We now ask. What part did societies and individuals play in the 

 advancement of our favourite work ? If we reply that little inter- 

 est was shown outside the circle of pure science, it must be borne 

 in mind that the bulk of mankind require strong and convincing 

 proofs of the value or charm of any study, before they incline to 

 patronise and cultivate it. Has the day come when such proofs 

 are forthcoming, and the value of the study is recognised ? I take 

 it that this meeting to-night shows that we are all animated with 

 the idea of stimulating others by our sympathy, or of helping each 

 other practically in all that pertains to the microscope. We have 



