60 The Microscope. 



increases, the mercuiy rises and stops the aperiure in the end of the 

 T piece — and thns the gas flame is lowered and an even temperature 

 maintained. The gas, is, however, not extinguished — as a small 

 hole in the side of the T, admits just enough to keep the flame 

 lighted. A thermometer is placed by the side of the regulator so 

 that the temperature of the water with which the can is filled, may 

 be determined — and the size of the gas flame regulated accordingly. 



The drawers should be partly filled with cotton in which the 

 eggs are placed and lightly covered. 



The water should be kept at 37° to 40° C. Hen's eggs thus 

 incubated hatch in about three weeks. Instead of the above home- 

 made apparatus, a patent incubator may be had at the outlay of 



a few dollai's. 



{To be Continued.) ^ H 



EDITORIAL. 



TN looking over the various text- books and other publications 

 -*■ dealing with microscopical subjects, one cannot fail to be im- 

 pressed with the clear, fine-cut appearance of the usual illustrations. 

 To one not familiar with the subject, a study of many of these 

 illustrations should lead him to the conclusion that microscopy, so 

 far as observation goes, is not a difiicult thing to master. And this, 

 indeed, has been the case, in our experience, with students who 

 have come to us for instruction in histology. The first rude 

 awakening often comes to the beginner when he takes his text-book 

 cut as a guide to lead him through the intricacy of his first mount. 

 Everything looks so differently from what he expected, and even the 

 instructor, in attempting to point out the features so clearly dis- 

 played in the cut, will, for some time meet with but feeble success. 

 It may be urged that the difficulty is that the eye requires a special 

 training to enable it to convey a correct impression under conditions 

 to which it is not at all accustomed. This is very true: but is it the 

 only reason for such complete ( and not uncommon ) failures to 

 see anything at ail ? It seems to us that one cause of 

 failure is to be looked for in the illustrations, and the reason is, 

 generally, that they are too diagrammatic. We think that the 

 better class of illustrations in question are very helpful to the 

 advanced worker, not because they are true pictures — for they are 

 not — but that he has learned to take something for granted and to 

 make just the proper allowances to enable him oftentimes to know 

 exactly what the artist intended. No specimen, however well 



