The Microscope. 237 



glass. Possibly further skill in handling may secure success, but I 

 cannot help but doubt the marked superiority of the objective over 

 the best of former manufacture in such a test as this. 



The results are admirable with eye-pieces of high power. I 

 used a one-fourth inch solid ocular with excellent effect, though gen- 

 erally I do not like the magnification at the upper end of the tube. 

 The objective works through cover glass one-hundredth of an inch 

 in thickness. 



Taken altogether, it will be seen that under the circumstances 

 detailed, the objective has shown itself to be of very high grade 

 among those of modern production ; but, judging by results obtained, 

 it can not reveal anything not heretofore seen under similar circum- 

 stances with the best work of at least six opticians. As an objective 

 for practical work I am greatly pleased with it, and see no cause for 

 hesitancy in purchase on account of the delicacy of its construction. 

 I think, however, it quite possible that the one-eighth of same make 

 may be still more serviceable for general use. 



Now, a word as to the eye-pieces, and this story, already much 

 too long, must close. Neither with the new objective nor with others 

 do I find any superiority over the common Huyghenian oculars in 

 the matter of fine and difficult resolution or definition, in the central 

 areas of the field. The color corrections, especially as shown towards 

 the margins are better, and there appears to be less curvatvire of the 

 image, requiring less focusing for the central and peripheral parts of 

 field. The greatest gain, it seems to me, is in the ease for the eye 

 with the highest eye-pieces. From my experience with the "12 " I 

 am disposed to order an " 18," though in practice I rarely use a 

 Huyghenian higher than an inch or about ten in magnifying power. 



Champaign, III. 



A PROTOPLASMIC RETICULUM. 



C. H. STOWELL. 



A FEW American histologists accept, in full, the teachings of 

 Heitzman, and others, concerning the presence of a living 

 protoplasmic reticulum in all the cells and tissues of the body. 



I would advise all such workers who are after the truth in the 

 matter, to procure a copy of the Dental Cosmos for June, and in it 

 read the excellent article bv Dr. Allan, of New York. 



