1885.] 



MICROSCOPICAL JOURNAL. 



95 



EDITORIAL. 



Publisher's Notices.— AU communications, re- 

 mittances, exchanges, etc., should be addressed to the 

 Editor, P. O. Box 630, Washington. D. C. 



Remittances should be made by postal notes, money 

 orders, or by money sent in registered letters. Drafts 

 should be made payable in Washington, New York, 

 Boston, or Philadelphia. 



Subscription-price before April ist, JSi per year, in 

 advance. All subscriptions begin with the January 

 number. After April ist the subscription-price will 

 be J1.50. 



The regular receipt of the Journal, which is issued 

 on the 15th of each month, will be an acknowledgment 

 of payment. 



The first volume, 1880, is entirely out of print. The 

 succeeding volumes will be sent by the publisher for 

 the prices given below, which are net. 



Vol. II (1881) complete, $1 50. 



Vol HI (1882) complete, f2. 00. 



Vol. IV (1883) complete, $1.50. 



Vol. V (1884) complete, Ji. 50. 



Vol. V (1884), Nos. 2-12, >i.oo. 



To Subscribers. — There are a 

 few of our old subscribers who are 

 disposed to take offence because their 

 Journal is stopped when subscrip- 

 tions expire. A very Httle considera- 

 tion will convince them that such a 

 rule is a perfectly just and proper one, 

 and also that, having made the rule, 

 it is not reasonable to expect us to go 

 all through our subscription-list and 

 select certain names to be excepted 

 from the operation of the rule. 



One subscriber writes that . he 

 ' shouldn't think it would pay ?' Per- 

 haps it does not. Nevertheless, we 

 have not time to look after the small 

 number of subscribers who fail to 

 renew each year. No doubt if we had 

 no other work it would pay to do so. 

 As it is, we assume that every sub- 

 scriber who wants the Journal will 

 take it. 



Microscopical Societies. — The 

 officers and members of microscopi- 

 cal societies are requested to aid us 

 in preparing a list of such societies 

 in the country for publication, as ex- 

 plained last month. It is desired to 

 make the list as complete as possible, 

 but no society will be entered in the 

 list until we have definite informa- 

 tion concerning its active existence, 

 which should properly come from 

 the Secretary or President. We do 

 not intend to copy from any old lists, 

 as it is only desired to publish the 



names of societies in existence each 

 year. As yet we have very few re- 

 sponses to our request last month. 

 If the Secretaries are not sufficiently 

 interested in this matter to enable us 

 to make a reasonably complete list 

 (which only demands a tew moments 

 of the time of each one), we will be 

 obliged to postpone it indefinitely. 

 o 



Objectives for Special Use. — 

 The wide-spread interest in the study 

 of bacteria with reference to their 

 morphology and their association 

 with diseases, has called forth many 

 private letters to the editor inquiring 

 what objectives are the most suitable 

 for such investigations. In view of 

 the importance of this subject to many 

 readers, we propose to offer a few 

 remarks in this place, but with much 

 diffidence, since our personal experi- 

 ence in this particular kind of exami- 

 nations has been extremely limited. 



In the first place we would say 

 that we cannot understand why an 

 objective of extreme angular aperture 

 should be required for this work. It 

 would seem that what is wanted is 

 not angular aperture but extreme 

 sharpness of definition, which can be 

 obtained quite as well with lenses of 

 moderate angular aperture. Whether 

 this is true or not we are not prepared 

 to assert in positive terms, but so far 

 as our experience goes it seems to be 

 so. Yet the fact is, that those who 

 are practically engaged as investiga- 

 tors prefer the high-power, homoge- 

 neous-immersion, wide-angle lenses. 

 For this reason we hesitate to advise 

 the purchase of any others for this 

 kind of work, although we can scarce- 

 ly resist the impression that the ad- 

 vantages of the homogeneous-immer- 

 sion lenses are due in great part to 

 their excellence as optical instru- 

 ments, rather than to their large an- 

 gle. As is well known, the use of 

 oil as an immersion medium gives no 

 little advantage to the maker, and 

 there is no doubt its benefits are felt 

 equally well in the making of lenses 

 of moderate angular aperture. 



