February 12, 1892.] 



SCIENCE. 



91 



on the lower side, lead smaller, well marked veins. There 

 is also a very slight point on the opposite side of the leaflet, 

 the venation here being similar to that just described 

 What, then, does this abnormal leaflet mean ? Can we not 

 see that nature has decreed that there shall be an increase in 

 the number of leaflets ? And that she is about to " cut off " 

 new leaflets from each side of this terminal leaflet ? 



Fig. 2 confirms us in this supposition, and furnishes an 

 objective demonstratian of a more advanced transition stage. 

 The sinuses have deepened, and the two lobes bid fair to be- 

 come separate individual leaflets. We feel secure in making 

 this statement because Fig. 3 stands ready to make good our 

 word with a newly-added leaflet on one side and another on 

 the other side, well under way. The rachis, meanwhile, has 

 elongated to make room for the new-comer. Fig. 4 illus- 

 trates a repetition of this process of division, adding empha- 

 sis to our explanation of these "abnormal leaves." Nature 

 is going right on, bent upon working out her conceptions to 

 the fullest extent. 



Nos. 5, 6, and 7 are certainly extremists. They may, 

 perhaps, be compared with the impulsive, rampant reformers 

 in the social world, who are imbued with a stronger pro- 

 gressive impulse than will harmonize with existing condi- 

 tions; whose wishes to sui-mount all obstacles and soar aloft 

 lead judgment and reason astray. The time is not ripe for 



LEAFLBTS FROM THE AILANTHUS TREE. 



such prodigious strides, and much effort is therefore expended 

 to little purpose. A few such leaders will occasionally be 

 found among plants, fore-runners, as it were, of future at- 

 tainment, and here we have leaflets which as yet have not 

 even attained to an individuality of their own, taking upon 

 themselves the work which legitimately belongs to the senior 

 members of the family; if we may designate a leaf as a little 

 family, and the leaflets thereof the individual members. No. 

 8 is such a senior member; that is, instead of a terminal 

 leaflet it is from the base of the leaf. It is better able to 

 take up the burden of secondary division than the mere baby 

 leaflets that have not yet learned to take care of themselves. 

 No. 8, however, may also be classed with the reformers, but 

 with that more reasonable class who are not entirely beyond 

 the ken of normal vision. 



Would we not, therefore, be led to draw this conclusion 

 from what we have said (and, I trust, demonstrated), that 

 pinnate leaves are developed by a division of the terminal 

 leaflet: the bi-pinnate leaf is evolved from the pinnate by 

 the division of the leaflets, normally beginning in the lower 

 or basal leaflets? That this is the law of division which holds 

 among the majority of pinnate leaves is quite commonly 

 demonstrated and verified by the leaves of various plants. 

 The leaves of the trumpet creeper furnish as good illustra 

 tions of these various stages of transition as the ailanthus 

 leaves. 



There is but a slight point on the lower or outer portion 

 of the typi'.-al basal leaflet of the ailanthus; this point is 

 crowned with a small gland; here seems to be the starting- 

 point of the new departure, which, according to the predic- 

 tion of No. 8, will, in the course of time, result in the evolu- 

 tion of a bipinnate ailanthus leaf. This secondary division, 

 as we have chosen to call the division of the lower leaflets, is 

 illustrated abundantly by the common elder (Sambucus 

 canadensis). So conspicuous, indeed, are the variations in 

 the elder that it deserves a chapter on its own progre.ssive 

 eft'orts ; it seems especially able to respond to favorable con- 

 ditions. Mrs. W. a. Kellerman. 



Columbus, Ohio. 



SUGGESTIONS AS TO TEACHING BOTANY IN 

 HIGH SCHOOLS. 



The teaching of botany in our colleges and higher schools 

 during the last twenty-five years has had the unfortunate 

 efi'ect of bringing the science into disrepute, and of engen- 

 dering in the minds of many who — as they would say — 

 " took"' it (like a dose of medicine), a thorough distaste for 

 it. It is only within ten years that any radical change has 

 taken place in the teaching ideals, and even to-day in many 

 of the best institutions of learning, conservatism forces in- 

 struction into the old channels. The lower schools have 

 travelled the same line, partly because they knew no better 

 way, and partly because they were meeting the demands of 

 the higher schools in the matter of preparation. 



The radical defect of the older teaching lay in the failure 

 to study the plants themselves; in the failure to treat them as 

 living organisms; and in the failure to take into account the 

 existence of other plants than the flowering ones. The ease 

 with which plants could be collected and preserved by drying 

 early led to the study of their external characters with a view 

 to their classification alone. From the earliest times, there- 

 fore, almost to the present day, classification has been looked 

 upon as the most important portion of the science of botany. 

 Now, however, that the economic importance of the study of 

 the physiology of healthy and diseased plants and of the 

 causes of disease is coming to be more generally appreciated, 

 it is high time that both in primary and secondary schools 

 those portions of the science be taught which have a vital 

 and vitalizing interest. 



What Text-Book Shall We Use ? 



The first question that is usually asked is, "What text- 

 book shall we use ? " It is a difficult question to answer, and 

 probably the best reply is, " Whatever text-book the teacher 

 can use best." There is no book known to me which pre- 

 sents the subject in just the way that I consider most impor- 

 tant. Probably the one of most general adaptability is 

 " Gray's Lessons in Botany.'' If the teacher is capable of 

 using them, either Bessey's "Essentials of Botany " or Camp- 

 bell's "Structural and Systematic ^Botany " may he recom- 

 mended. Wood's " Lessons in Botany," revised, is unfit for 

 use on account of the numerous and misleading blunders 

 which it contains. There should be in the school library, 

 for reference, Gray's " Structural and Systematic Botany," 

 Goodale's " Physiological Botany," Bessey's "Botany," and 

 Goebel's "Outlines of Classification." Miss Newell's "Out- 

 line Lessons in Botany" will be found suggestive to the 

 teacher who knows nothing of the method of study suggested 

 herein. 



The suggestions here made are based on the supposition 



