i6 



SCIENCE. 



[Vol. XIX. No. 466 1 



tue hand and fingers in attempting to draw it. The " draw- 

 ing " was simply the vaguest and most general imitation of 

 the teacher's movements, not the tracing of a mental picture. 

 And the attempt was no better when a " copy " was made by 

 myself on the paper — a rough outline drawing of a man, etc. 

 There was no semblance of conformity between the child's 

 drawing and the copy. Farther, while she could identify 

 the copy and name the animal, she could not identify her 

 own effort, except so far as she remembered what object she 

 set out to make. 



But in the next week (early iu the twenty-seventh month) 

 a change came. I drew a rough human figure, naming the 

 parts in succession as they were made: she suddenly seemed 

 to catch the idea of tracing each part, and she now for the 

 first time began to make figures with vertical and horizontal 

 proportion; i.e., she followed the order she saw me take: 

 head (circle), body (ellipse) below, legs (two straight lines) 

 further below, hands (two lines) at the sides of the body. 

 It is all done in the crudest fashion, but that is due to the 

 lack of muscular coordi nation. With the simplification of 

 the figure by breaking it up into parts came also the idea of 

 tracery imitation, and its imperfect execution. 



As yet, however, it is limited to two or three copies — ob- 

 jects which she sees me make. That it is not now simply 

 imitation of my movements is evident from the fact that she 

 does not imitate my movements: she looks intently upon the 

 figure which I make, not at my movements, and then strives 

 to imitate the figure with movements of her own very differ- 

 ent from mine. But she has not generalized the idea away 

 from particular figures, for she can not trace at all an alto- 

 gether new figure in right lines. Further, she traces these 

 particular figures just as well without written copies before 

 Jier; here, therefore, is the rise of the tracery imitation of 

 her oxen mental picture — a fact of great theoretical interest. 

 This illustrates again the point so strangely overlooked by 

 vrriters on the rise of volition that the earliest voluntary acts 

 are not voluntary movements. The thing pictured and 

 willed here is not a movement, it is a figure — man, bird, 

 clog. This figure suggests (stimulates) its motor associates. 

 It is only later that the muscular movement becomes con- 

 scious end. 



In the nature of the movements which the child has made 

 in this series of drawings there is a marked change and de- 

 velopment. There is growth from angular straight lines to 

 curves, from movements one way exclusively to reverse 

 movements, and an increasing tendency to complex intricate 

 figures, which last probably results from greatly increased 

 ease, variety, and rapidity of movement. At first she made 

 only sweeping "arm-movements," then began to ilex the 

 wrist somewhat, and now, with no teaching, she manipu- 

 lates the pencil with her fingers considerably. This seems 

 to give support to the opinion of professional writing-teach- 

 ers that the " arm-movement " is most natural and eflFective 

 for purposes of penmanship. 



Further, all her curves are made by movements from left 

 to right going upward and from right to left downward. 

 This is the method of our usual writing as contrasted with 

 "backhand." She also prefers lateral to vertical move- 

 ments on the paper. Her most frequent and easy " draw- 

 ing" consists of a series of rapid right-and-left strokes almost 

 parallel to one another. J. Mark Baldwin. 



A FEW CHARACrEEISTICS OF THE AVIAN 

 BEAIN.^ 



When we compare the brain of a crow or a titmouse with 

 the brain of a snake or a turtle, it is no longer a marvel that 

 birds bear towards their reptilian cousins the relation of in- 

 tellectual giants to intellectual dwarfs. The cranium of 

 reptiles is small, while the bra'.n-cavity of birds is large, and, 

 what is more pertinent, the whole of that cavity is filled with 

 a compact brain mass. Not only that, but the cerebrum, the 

 seat of the intellectual faculties, constitutes the major portion 

 of that mass. 



The cerebrum is composed of two lateral halves or hemis- 

 pheres, which are so situated that they form a compact heart- 

 shaped mass. The apex of this heart is directed towards the 

 bill of the bird, while the notch is directed towards the tail. 

 These hemispheres are unconvoluted, but the borders of some 

 of the superficial lobes approach almost to the dignity of con- 

 volutions. Furthermore, a microscopic study of the brain 

 reveals the fact that occasionally there occu^s a blind convo- 

 lution ; i.e., an internal projection of gray matter without a 

 concomitant surface convolution. 



A microscopic study of the bird brain does not reveal a cere- 

 bral cortex similar to that of the human cerebrum. Here the 

 cerebral cortex is represented by a thin hull containing sev- 

 eral loosely aggregated cell-clusters. These cell clusters are 

 constant and are homologous to corresponding clusters in the 

 lizard brain. 



Next in size to the cerebrum comes the cerebellum. Not 

 only is it transversely convoluted, not only is it a cover for 

 the medulla, but it is also partly wedged into the notch 

 between the two halves of the cerebrum. This high develop- 

 ment of the cerebellum of birds, coupled with the correspond- 

 ing high development of the cerebellum of Bshes, is a strong 

 argument in favor of the hypothesis that the cerebellum 

 functions as a co ordinating centre for muscular movements. 



Neurologically considered, birds are pre-eminently seeing 

 animals, and all parts that appertain to vision are highly 

 developed. The optic nerve is the largest cranial nerve, and 

 the optic lobes are completely differentiated bodies. Even 

 the third, fourth, and sixth cranial nerves, although quite 

 small, are relatively larger than the corresponding nerves of 

 the mammalian brain. 



An extraordinary development of one set of organs is 

 never accomplished but at the expense of some other set. In 

 this case the organs of the sense of smell have been the mai'- 

 tyrs. Although in the lower avian types the olfactory lobes 

 are paired and conspicuous, yet in the highest types of birds 

 they have been reduced to a small impaired body which is 

 partly imbedded in the base of the cerebrum. 



These two facts lend support to the view that birds of prey 

 find their food more by aid of the sense of sight than by aid 

 of the sense of smell. The birds of prey are far from the 

 lower end of the scale, and in all cases examined the olfac- 

 tory lobes have been relatively smaller than the correspond- 

 ing lobes of chickens, geese, turkeys, etc. I have not yet 

 examined a buzzard's brain ; but, judging by the figures of A. 

 Bumm," they have small, inconspicuous olfactory lobes. 



From the above statements, we see that economy of space 

 is evidenced in all parts of the avian brain. Indeed "pro 

 gressive compactness" has played so important a part in the 

 evolution of birds that there is a vast difference between tlie 



1 This is but a brief abstract of a portion of my paper upon tlie *' .Mocphol- 

 ogp of the Avian Brain," Journal of Comparative Neurology, vol. I., pp. 39 9?, 

 10T-:34, 265-286, pi V.-VIII., XIV. -XVI., XVIII. 



= Das Groshirn der Vsgel, Zellsohrlft f. Wlss. Zoologle, BJ. xxxvlii., 18S3. 



