and Laboratory Methods. 



1159 



demand for information concerning the methods employed increases until micro- 

 scopical journals find it advantageous to assign a separate department to the 

 discussion of methods and apparatus involved in the production of scientific 

 photographs. It is a matter of congratulation that workers in this country are 

 now afforded such a means of communication through the columns of the 

 Journal of Applied Microscopy and Laboratory Methods. 



The department here being new, it is but natural that matters of an elementary 

 nature should be discussed. With this in mind, I have thought to describe an 

 actual installation of apparatus for high-power photo-micrographic work and to 

 exhibit some of the results attained by its use. In Vol. Ill, No. 5, of the 

 Journal appeared an account of the outfit employed in the Johns Hopkins labora- 

 tory. The one at the University of Kansas is very similar, but it has been 



1 • 





Figure 1. — Spermatogonia! mitoses of the grasshopper, j¥z>/«c?^r p/iaiiho/'/erus, in the metaphase and 



anaphase. These divisions take place very rapidly and the archoplasmic threads of previous 



spindles may still be seen between the centrosomes of different cells, 1000 diameters. 



further modified from the original Zeiss arrangement than has the one at 

 Baltimore. Upon the optical bench are placed the illuminating apparatus, two 

 iris diaphragm supports, and the microscope. The other accessories furnished 

 with the complete outfit are not employed. The camera itself has not been 

 altered. 



Following is the arrangement of the apparatus : The microscope — I use a 

 Van Heurck — Watson stand — is firmly clamped on the end of the bench nearest 

 the camera. Next, the carbons of the arc light are roughly adjusted so as to lie 

 approximately within the optical axis of the microscope. With a low power 

 objective focused upon the object, the arc is projected upon a small screen 

 suspended upon the front of the camera which is pushed back on its sliding bed 

 to a distance. By means of the adjustment screws, the arc is then brought into 

 such a position that the glowing crater occupies the center of the field. Prelim- 



