2700 Journal of Applied Microscopy 



light fades out ? Compare it with the one in darkness. Thus it will be seen 

 that sunlight when too intense will rapidly change the character of chlorophyll, 

 although it is generally absolutely necessary for its development. 



cm. Latex. 



1. Take one of the large, red, deciduous stipules which cover the terminal 

 bud of Fines elastica at the time when it is becoming transparent, a few days 

 before it is ready to fall. Examine immediately by holding the stipule with the 

 inner side up on the stage of the microscope and examine with low and high 

 power. Note the complex system of lactiferous ducts and the movement of the 

 latex in them caused by its escape from the torn end of the stipule. At times 

 the flow in the ducts appears to be very rapid. 



2. Mount some of the latex and examine under high power. Note the 

 spherical granules and draw. These are the rubber globules. 



3. Why does the stipule become colored before it drops off from the bud ? 



CIV. Pollcntubes in Artificial Cultures. 



1. From an opening anther take fresh pollen of Canna, Hyacinth, or Bego- 

 nia and make cultures in the following solution : 



a. Cane sugar . _ . _ (3 parts. 



b. Gelatin . . . . . 3 " 



c. Tap water ----- 91 " 



Heat the mixture over a water bath till the gelatin is dissolved. 



2. To a centimeter or two of this solution add an equal quantity of tap 

 water and filter into a small covered dish. Put the pollen into the solution and 

 also make hanging drop cultures, placing the slides into a moist chamber. 



3. In 20 to 24 hours examine and draw several tubes representing succes- 

 sive stages of development. Note the rotation of the cytoplasm. 



4. Treat with iodin solution and note the position of the nuclei. 



Ohio State University. JOHN H. SCHAFFNER. 



CURRENT BOTANICAL LITERATURE. 



CHARLES J. CHAMBERLAIN, University of Chicago. 



Books for Review and Separates of Papers on Botanical Subjects should be Sent to Charles J. 

 Chamberlain, University of Chicago, Chicago, 111. 



Holden, R. J„ and Harper, R. A. Nuclear divis- At certain stages in the life history of 

 ions and nuclear fusion in Co/eospcviiuii . . ^ ^i i, ^ • ^ i • 



so,nhi-arvensis,l.^y. Trans. Wisconsin Acad. ^^IS rust, the Cells Contain tWO nuclei 



of Sciences, Arts and Letters, 14: 63-82, pis. and at Other Stages but one nucleus. 

 ~^' ^ ^' The uredospore, and the cells of the 



mycelium to which it gives rise, contain two nuclei which divide by conjugate 

 division, i. e., each nucleus contributes to the two daughter cells. The teleuto- 

 spore produced from this mycelium is the last binucleated cell of the series. 

 The two nuclei of the teleutospore fuse, after which the teleutospore at once 

 germinates into a four-celled promycelium, each cell of which contains but a 



