Journal of Applied Microscopy. 



11 



on the stand. A brass plate with suita- 

 ble incisions is placed over the stopper 

 to prevent the wires from cutting into it. 



As a safeguard against possible im- 

 perfections in the glass, it is advisable 

 before applying the pressure to cover the 

 entire apparatus with a suitable box. 



The described glass cylinder can be 

 procured from Greiner & Friedrichs, in 

 Stutzerbach. Thuringia, for about two 

 marks. 



An Improved Paraffin Imbedding 

 Dish. 



The ordinary paraffin imbedding box 

 made of a glass plate and two small 

 metallic L's, is very deficient for practi- 

 cal work. This is especially true when 

 large quantities are to be imbedded for 

 class use or for special investigation. 

 Petri dishes 80, 120 and 150 millimeters in 

 diameter, answer the purpose quite well, 

 as large cakes containing many pieces 

 of tissue can readily be made in them; 

 but when using the petri dish, it is often 

 difficult to remove the paraffin cakes, es- 

 pecially if the walls of the dish are not 

 perfectly regular. The dishes are also 

 easily broken and the bottom cannot be 

 removed so as to secure more rapid con- 

 gealing of the paraffin. 



In order to secure the advantages of 

 the petri dish and at the same time 

 avoid the disadvantages mentioned 

 above, I have devised a paraffin imbed- 

 ding dish which I think will be found 

 very convenient. (Fig. 1.) The bottom 



Fig. 1. 



is a square glass plate of proper size 

 and thickness, while the box consists of 

 an open brass ring with a thumbscrew. 

 The sides of the ring should be smooth 

 and should be of sufficient thickness to 

 secure rigidity. About two or three mil- 

 limeters is the proper thickness. It will 

 be found most convenient to have the 

 rings of three diameters, 80, 120 and 150 

 mm. Before imbedding, apply a very 

 thin coat of glycerine to the parts with 

 which the paraffin will come in contact 

 and pour in a suitable amount of paraf- 

 fin to make the cake. The objects should 

 be in a bottle with a cork. Turn the 

 bottle upside down and allow the objects 

 to settle on the cork. Then remove the 

 cork and let the paraffin in the bottle 

 with the objects fall into the dish. The 

 objects may be arranged in the paraffin 



with hot needles. Put the dish quickly 

 into cold water, but do not let the water 

 flow into the dish until the paraffin is 

 hard enough to bear the weight of the 

 water without being distorted. In a 

 short time the glass plate may be re- 

 moved, thus permitting the under side of 

 the cake to cool more rapidly. After the 

 cake is thoroughly hardened it can 

 easily be removed from the brass ring 

 by loosening the thumbscrew. 



John H. Schaffner. 

 Botan. Laboratory Ohio State Univer- 

 sity, Dec. 3, 1897. 



DISCUSSION. 



Papers upon live subjects within the province of 

 the Journal will be printed over the author's 

 signature. 



The Microscope in the High 

 School. 



The most important pedagogical ad- 

 vance which has been made in science 

 teaching in high schools during the last 

 decade is unquestionably the introduc- 

 tion of laboratory methods in the bio- 

 logical studies. Begun in the largest 

 and most progressive high schools, the 

 new method has now been adopted by all 

 but the least progressive teachers. In 

 botany, zoology and physiology, the 

 study of definitions, systematic descrip- 

 tions and detailed accounts of how or- 

 g'anisms look and act, have been sub- 

 ordinated to the direct observation and 

 study of the organisms themselves. Each 

 student now sees for himself the fact 

 which he hitherto has only read about in 

 his text-book. Science has come to be 

 taught as science, rather than as litera- 

 ture. The student has become an origi- 

 nal investigator in place of a mere mem- 

 orizer of descriptions. Now, his faculties 

 of observation, judgment and descrip- 

 tion are trained and developed, where 

 formerly only his memory was culti- 

 vated. This change in the method of 

 teaching has necessitated a change in 

 the means of its application. The text- 

 book is now superseded by and made 

 secondary to, the specimen itself. The 

 latter is more thoroughly studied and 

 more frequently consulted than the for- 

 mer. Just as the laboratory study of 

 physics, as contrasted with the ancient 

 text-book method of studying the sub- 

 ject, has made necessary an elaborate 

 equipment of apparatus for experiment 

 and for the demonstration of physical 

 laws, and just as modern methods of 

 teaching chemistry require that the stu- 

 dent shall have all the appliances needed 

 by the practical chemist and investiga- 

 tor himself, so in the biological sciences 

 the microscope and the scalpel and for- 



