1886.] 



MICROSCOPICAL JOURNAL. 



119 



— We learn that Miss M. A. Booth re- 

 ceived a diploma for microscopic mounts 

 at the New Orleans Exposition, and also 

 a badge of first honorable mention in the 

 woman's department. 



— The method of distinguishing be- 

 tween true and artificial or adulterated 

 butter described by Dr. Thomas Taylor 

 still holds good, notwithstanding certain 

 newspaper articles to the contrary. Re- 

 cently Prof. Weaver, of Columbus, Ohio, 

 stated that he had made an observation 

 that ' destroys in a great measure the use- 

 fulness of Dr. Taylor's discovery.' On 

 submitting the matter to careful examina- 

 tion, it appears that Dr. Taylor's method 

 is perfectly reliable, but it should be car- 

 ried out as Dr. Taylor describes, and not 

 as Prof. Weaver does it. 



— Mr. Douglas H. Campbell, is the au- 

 thor of an interesting article on the devel- 

 opment of the antheridium in ferns, pub- 

 lished in the April number of Bidlctin of 

 the Torrey Botanical Club. He advises 

 to use dioecious species or the young pro- 

 thallia of the monoecious species. The 

 prothallia are obtained by sowing the 

 spores in fine earth kept moist. They 

 germinate in from three days to a week, 

 and in six weeks are in a condition to 

 study. They are examined in water. The 

 processes of forming the antheridium and 

 the escape of antherozoids are described 

 and illustrated. 



CORRESPONDENCE. 



Cement for Mounting. 

 To THE Editor : — Some six or seven 

 years ago I began to use the white zinc 

 cement for mounting slides. It is one of 

 the neatest and prettiest finishers I know, 

 in spite of one or two drawbacks, and has 

 also the merit of cheapness — a great ad- 

 vantage in class work with ordinary stu- 

 dents. I then mounted a great many 

 slides and have a few of them now in 

 very good condition. About two years 

 ago, my stock of this cement being low, 

 I bought some more benzole and made a 

 fresh lot. My surprise and disappoint- 

 ment were, however, great when I found 

 that the new cement was quite worthless. 

 After mounting several specimens and 

 putting them aside for a week or two, the 

 cement invariably became full of bubbles 

 so that I could wipe off the whole of it 

 with my finger. I lost them all. Sup- 

 posing that the fault was in the new ben- 

 zole, I obtained some more but had no 

 better success. I next applied to a good 



firm in Philadelphia and obtained three 

 specimens of their best benzole, but the 

 same failure attended the attempt. In 

 one case, however, the bubbles only ap- 

 peared around the edge of the cover- 

 glass. This was, nevertheless, enough to 

 allow the escape of the liquid and to ruin 

 the slides. I think the difficulty must be 

 connected in some way with the addition 

 of the white zinc, because it does not oc- 

 cur in the damar varnish if used without 

 this ingredient. 



The trouble and loss have been so 

 great that I have almost dropped the use 

 of this kind of cement, much to my re- 

 gret. If you, or any of your readers, 

 can give me some advice that will relieve 

 the difficulty I shall be much indebted to 

 you for communicating the same. 



Akron, O. E. W. Claypole. 



American Society of Microscopists. 



To THE Editor : — I desire to announce 

 that the place and time of the Ninth An- 

 nual Meeting of the American Society of 

 Microscopists have been determined by 

 the Executive Committee. The Society 

 will convene at Chautauqua, N. Y., Au- 

 gust loth, at lo o'clock A. M., and con- 

 tinue its sessions at least four days. 



This famous resort is so readily acces- 

 sible, the fact that railway fares to Chau- 

 tauqua are always greatly reduced, and 

 the privilege of spending the week of 

 meeting away from the heat and confu- 

 sion of a large city, will, it is expected, 

 secure a large attendance, and make this 

 annual gathering unusually interesting. 



Letters of incjuiry addressed to the 

 Secretary will be promptly and cheerfully 

 answered. 



D. S. Kellicot, Sccr. 



Buffalo, N. Y. 



On Fine Measurements. 



To the Editor : — I have read with 

 great interest Dr. Shanks' ' Contribution 

 to Blood Measurement,' in the February 

 issue, and am glad to see so full a state- 

 ment of the methods used, which, in my 

 opinion, adds much to the scientific value 

 of the work clone. I think, however, the 

 Doctor does not measure a sufficiently 

 large number of corpuscles at one sit- 

 ting to be certain that he has arrived at 

 the true average in any one instance. 



I hope the Doctor will favor us with 

 more definite information as to the screw 

 in his micrometer. Does he mean that it 

 is absolutely without error ? And are we 

 to understand that his standard stage 

 micrometer is free from all errors ? I have 



