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mean a direction of observation into channels of im- 

 portance, channels not filled by work already done. 

 This " rationality" will come to the tyro who both 

 studies and observes. 



As I know that the unbotanical and junior students 

 are entirely ignorant of what "critical botany" means, 

 and as science sadly needs more critical observers, I 

 thought Science-Gossip would be the best medium 

 for a few notes on the subject. 



Criticalness is necessary in all branches of the 

 science. In the chemistry of plant-life, it is not 

 enough to know that certain elements occur in certain 

 plants. We want to know in what proportions they 

 occur, in what manner of composition, at what periods 

 of the life of a plant, and in what organs or tissues. 

 We want to know where the plant gets them, how it 

 assimilates them, what changes they undergo in the 

 plant, and whether they are essential to its life. This 

 amounts to a want — very partially supplied at present 

 — of detailed chemical analysis of various tissues and 

 organs of many different species at various stages of 

 growth and decay, and an extended practice of the 

 valuable experiments in "water-culture," the growth 

 of various plants in definite solutions. 



In general Morphology or Minute Anatomy, we 

 must not rest content with knowing that such and such 

 a member is built up of such and such tissues, or that 

 these latter are composed of various lamina; of cells 

 or vessels of different shape or structure. We want 

 also to see the mode of development of each cell, 

 how they make up the vessels and tissues, and how 

 the complex member arrives at its complexity. Not 

 only is there room for additional research on the 

 functions and behaviour of the nucleus of cells and for 

 further elucidation of the histoiy of starch, but the 

 subject of the crystalloid granules, the aleurone 

 particles, and the "raphides," or true crystals, con- 

 tained in the cells of many plants, is a mine but 

 slightly worked. Systems of branching and phyllo- 

 taxis are also lines— among many I might mention 

 — in which there is yet much to be done by accurate 

 observation, especially that of development. 



In elementary Physiology, science stands in need of 

 help, rather from experiment and statistics than from 

 pure observation ; such as the experiments of Pro- 

 fessor McNab on the movement of water in plants 

 {Trans. Hoy. Irish Acad., vol. xxv.), those of Sachs 

 on the corroding power of roots, and of Mr. Darwin 

 on twining plants. 



In special Morphology and Physiology, however, 

 there is an inexhaustible field for new and valuable 

 observation. The life-history of the lowest plants, as 

 studied by Messrs. Dallinger and Drysdale ; the 

 hybridization of ferns and flowering plants, both in 

 cultivation and in a wild state; the homology of 

 certain special organs, in various groups, worked out, 

 as Mr. S. H. Vines has done that of the suspensor 

 (Quart. Journ. Micros. Set., Jan., 187S) • the 

 minute anatomy of the leaf as a classificatory cha- 



racter, as Professor McNab is proving it among the 

 Conifers ; the floral development and teratology, or 

 abnormal forms, of various groups, studied on the 

 method inaugurated in Payer's Organogenic de la 

 Flair, excellent examples of which may be seen in 

 Dr. Masters's paper on Primula, just issued, in the 

 Transactions of the Linmxan Society, in his note on 

 the Composite, in the Journal of Botany for Feb- 

 ruary, and in Mr. Hartog's paper on the Sapotacese, 

 in the same journal for March : these are a few of the 

 wider subjects for critical study. Here it will be seen 

 that it is often necessary that observations should be 

 both numerous and even continuous, and that they 

 should be compared one with another. 



But even in the simpler and isolated observations 

 of the collector and tyro, the critical faculty comes 

 equally into play. I call it a faculty, for, like the 

 imagination of the poet, some people seem to be 

 utterly destitute of it ; but I have little doubt that 

 this arises, mainly, from its never having been culti- 

 vated, educed, educated. If you have a garden, and 

 are likely to remain in one locality for years, you may 

 render much service to botanical science by observing 

 the exact date of the opening of leaf-buds and Sower- 

 buds in various species in each year, noticing also the 

 altitude above sea-level, latitude and soil of your 

 garden; and, if possible, other meteorological details, 

 such as rainfall, thermometric and barometric obser- 

 vations, wind, &c. If you can name, or capture and 

 get named, the various insects which feed upon your 

 plants, or which visit their flowers, distinguishing 

 those that suck the honey, those that eat and those 

 that cany away the pollen, you will also be doing 

 good scientific work. 



If you collect wild plants, it is important to notice 

 the altitude at which a species occurs, the nature of 

 the soil it grows in, and its exact topographical posi- 

 tion, so that it can be seen, not only in what county 

 and parish it occurs, but also in what river- basin ; 

 since the vast importance of river-basins in the dis- 

 tribution of plants is now generally acknowledged. 



Lastly, it is important to note exactly what your 

 find is. This is what English botanists generally 

 speak of as critical knowledge. You must make 

 yourself sure, not only of genus and species, but in 

 many cases of sub-species, variety, or variation. To 

 do this is time well spent. It makes you examine 

 a plant more closely than if you already knew it well, 

 were told its name or identified it, as some tyros do, 

 from its general resemblance to a picture. 



By this close examination you unconsciously gain a 

 far deeper and more permanent knowledge of a plant 

 than by being told its name ; and, moreover, your 

 accurately determined locality for one of these 

 "segregates," as they are termed, may be of great 

 use in the generalizations of botanical geography. 

 Independently, therefore, of any theory as to the 

 origin of species, it is far better, from the pewst of 

 view of self-education and instruction, to be a 



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