February 12, 1892.] 



SCIENCE. 



93 



How to Begin. 



It matters little what part is selected for a beginning. As 

 the study commences in winter, the shoots of trees, two or 

 more feet long, may be used. Select a tree in which the 

 scars left by the fall of the foliage, leaves, and bud scales of 

 the preceding season are quite conspicuous, such as the cot- 

 tonwood, poplar, hickory, or horse-chestnut. Set the stu- 

 dents at work to examine these before they have been as- 

 signed any study in the book. Have them examine all the 

 markings they can find; compare the buds; study the rela- 

 tion between the buds and the scars; determine the extent of 

 the preceding season's growth and of the season before that. 

 When as much of the e\ternal anatomy has been seen as 

 possible, let them carefully dissect the buds, studying the 

 nature and shape of the scales; the character of their sur- 

 faces, whether hairy or resinous ; the young foliage leaves 

 for the next season ; the young stem, comparing' the shoot 

 for the coming season with last season's growth, noting 

 differences and resemblances. This dissection should be 

 made partly by tearing off the parts, partly by cutting thin 

 slices crosswise and lengthwise with the knife. 



When the students have seen everything that they think 

 there is to be seen, let them write a description of what they 

 have observed. They should be asked to make this descrip- 

 tion as terse as possible, using their own language and not 

 resorting to the book for terms. 



The teacher should then examine these descriptions, in 

 which he will doubtless find much omitted. I should then 

 make the study of the same shoot the subject of the next 

 class exercise, in which I should point out each feature that 

 I wished examined, giving sufficient time for the inspection 

 of each part. I should also endeavor to show that for the 

 circumlocutions in their descriptions there are often single 

 words (technical terms). The pupils will thus come to know 

 something of the method of accurate and thorough observa- 

 tion, and will discover that technical terms are not hard 

 words invented for their discomfiture, but short ways of ex- 

 pressing the ideas gained. 



At the close of this exercise I should call upon each pupil 

 to draw carefully a portion of the shoot showing as many of 

 the facts observed as possible. Drawings should also be made 

 of the dissected parts. Here the teacher will be met by the 

 objection on the part of the pupils that they cannot draw ; 

 but as that is only another way of saying that they cannot see 

 accurately, he will have to insist on their doing the best they 

 can, with the assurance that as power of accurate observa- 

 tion increases the accuracy of the drawings will increase in 

 the same ratio. He should be able to lead here as at other 

 difficult places. Happy he if he be not a blind leader of the 

 t blind. 



After studjing several other shoots in the same way, I 

 should assign the lesson in the text on buds and branching. 



The points specially emphasized here are: 1. Study of the 

 plants themselves. 2. Drawing and describing observations. 

 3. Afterwards the study of the text book. 4. Supplementary 

 reading, particularly as to the function of the parts studied. 



Topics for Further Study. 



Following this method with each organ, the following 

 topics are suggested : 



Underground stems : potato (tuber); onion (bulb); cy- 

 clamen or Indian turnip (corm). 



Structure of stems : cut thin slices of both herbaceous and 

 woody stems and examine in water. Bean, sunflower, gera- 

 nium, hyacinth, and twigs of forest trees may be used. 



Leaves: structure of blade and petiole; forms of stipules; 

 character of venation, particularly with reference to function 

 of veins. Reference readings on the function of foliage 

 leaves are particularly important. Study of the unfolding 

 leaves in spring is specially desirable. 



Floivers : parts; forms; flower clusters, etc. I need enter 

 on no details as to these parts, since they are treated so fully 

 and have always received overmuch attention because of their 

 importance to classification. 



Let it be remembered in the study of all these topics that 

 it is not a memorizing of the technical terms of descrip- 

 tive botany that is wanted, but a study of structure of the 

 parts with reference to function. Insist on the pupil con- 

 stantly asking himself, "What is this for?" As to technical 

 terms; if they are not acquired as a convenience they would 

 better not be acquired at all. 



Some time should be taken before the close of the year to 

 study the lower plants. It is an excellent plan in the spring 

 to organize "forays," on which pupils can collect every form 

 of plant they can lay their hands on, ferns, toadstools, 

 lichens, parasitic fungi, algaj, etc. Preserve these^ and have 

 them studied. Directions for such study can be found in 

 Arthur, Barnes, and Coulter's "Plant Dissection" (Henry 

 Holt &, Co.); Bower's "Practical Botany" (Macmillan & 

 Co.); Bessey's " Essentials of Botany" (Holt); Campbell's 

 "Structural and Systematic Botany " (Ginn & Co.). 



Questions will be freely answered regarding any matters 

 not elucidated above, and further suggestions will be made 

 if desired. I should be glad to be of assistance to teachers in 

 improving the work in botany. 



Chaeles Eeid Barnes, 

 Professor of Botany in the University of Wisconsin. 



A NEURO-EPITHELIOMA OF THE RETINA. = 



The possibiMty of the reproduction of the most highly organ- 

 ized structure of the human body has long been doubted and even 

 denied. Until the publication of an instance by Professor Klebs 

 of Zurich, in which the ganglionic cells of the central nervous 

 system were found repealed in a tumor formation, this was not 

 admitted to be possible. Even now not a few competent patho- 

 logical bistologists are not convinced of its occurrence. An in- 

 teresting and important addition to this subject is that of Dr. 

 Flesner. In this instance the rod and cone layer and the external 

 nuclear layer of the retina were reproduced in a tumor. 



The case was that of a child four months old. One eye was 

 affected and removed, and then the remaining eye became the 

 seat of a disease presumably of like nature. But nothing was 

 permitted to be done for the second eye. Several years before 

 this child was born another child in the same family, this one six 

 months old, died in consequence of an eye tumor which returned. 

 Two years after the case just related another child of the same 

 parents, this one four months old, liad a tumor of the eye which 

 spread to the brain, also resulting in death. The one which is 

 reported makes, therefore, the third instance of eye tumor in this 

 family. There was no history of e.ye tumor in the immediate 

 ancestors of the children. 



The vitreous chamber of the eye was filled almost entirely with 

 the growth, The latter was attached to the retina throughout a 

 considerable part of its extent, and was seen to originate at a point 

 of microscopical size situated in the external nuclear layer. The 

 cells which made up the tumor consisted of two principal kinds. 



1 Every teacher shouli have some book with directions for preserving 

 plant?. The following are available: Bailey's -'Collector's Uaud-book" (Bates, 

 Salem, Mass.); Penhallo-w's " Botanical CoUeclor's Guide" (Renouf, Montreal); 

 Kuowlton's " Directions for Preserving Recent and Fossil Plants'' (Part B, Bul- 

 letin 39, U. S. National Museum). 



^ " A Peculiar Glioma (Neuro-eplthelloma?) of the Retina," by Simon 

 Flesner,M.D., fellow In pathology. From the Pathological Laboratory of the 

 Johns Hopkins University and Hospital. The Johns Hopkins Hospital 

 BuUetlD, No. IS, 1891. 



