60 



THE AMERICAN MONTHLY 



[March. 



sented a slide of Stotnoxys calcitratis, and 

 gave the characteristic differences of the 

 two genera, Stonioxys and Miisca, espe- 

 cially of the mouth-parts as adapted to 

 biting. He also called attention to the 

 position of the teeth and their distinctive 

 arrangement. The entire evening was 

 devoted to the subject, and slides of a 

 large number of species of different 

 genera were exhibited. 



John Walker, Seer. 

 Sax Francisco. 

 At a meeting held January 27th, micro- 

 scopes by Bausch and Lomb and by 

 Zeiss were shown and commented upon. 

 Dr. Ferrer gave an account of Koch's 

 method of gelatin culture. After alluding 

 to the disadvantages of the fluid media 

 method, still adhered to by Pasteur and 

 his followers, a brief sketch was given of 

 the gradual evolution of the gelatin 

 method, from the first tentative efforts of 

 Krebs and Brefeld up to the perfecting 

 of the present admirable system by Koch, 

 who was the first, practically to realize 

 the advantages offered by a culture me- 

 dium sufficiently transparent to admit of 

 direct microscopical examination, and at 

 the same time sufficiently non-fluid to 

 facilitate the growth of different germs in 

 separate colonies. After giving formulae 

 for the preparation of the gelatin, and 

 describing the methods of its sterilization. 

 Dr. Ferrer outlined the subsequent pro- 

 cedure, which is briefly as follows : — A 

 small portion of the bacterial material 

 about to be studied is transferred by 

 means of a previously-heated platinum 

 needle to some culture-gelatin placed in 

 a test-tube and rendered fluid by warmth. 

 The germs thus introduced are distributed 

 as evenly as possible throughout the 

 liquified gelatin, and this is then poured 

 upon a glass pl?te about 4-5 inches 

 square, and is there spread out in a thin 

 layer. The plate is then covered by a 

 bell-glass to exclude dust and undesired 

 germs. The gelatin solidifies on cooling, 

 and the various germs contained therein 

 multiply into separate colonies. The 

 growth of these can be watched at any 

 time under the microscope. While some 

 accidentally introduced forms will occa- 

 sionally be found, yet the majority of the 

 colonies will be seen to be those of the 

 organism specially inoculated. From 

 the latter a small portion is taken by a 

 sterilized platinum needle and with this 

 is inoculated a previously prepared test- 

 tube partially filled with sterilized gelatin. 

 In this the organisms thrive and multiply 

 and thus is obtained an absolutely pure cul- 



ture of the desired germs. The mouths 

 of the test-tubes are closed with cotton, 

 previously sterilized ; the platinum nee- 

 dles are intensely heated just before use, 

 and in fact at every step of the process the 

 * very greatest precautions are taken to pre- 

 vent the introduction of undesired germs. 

 It is an interesting and very important 

 fact that nearly all bacterial organisms 

 show distinctive peculiarities in the meth- 

 ods of their growth in gelatin. Some 

 liquify the culture medium, others do not, 

 and those of the latter class are especially 

 characteristic in the appearance of the 

 colonies. 



A. H. Breckenfeld, Rcc. Seer. 



NOTICES OF BOOKS. 



The Physiological Action of ike Differ- 

 ential Pneumatic Process on the Circu- 

 lation. By E. Fiegel, M. D. 



Pneumatic Therapeutics. By Alfred S. 

 Houghton, M. D., and P. C. Jensen, M. 

 D. 



Two pamphlets reprinted from Xhtjourn. 

 Amer. Med. Ass. 



The Physics of Pncuniatic Differentiation- 

 By Joseph Ketchum, and the Present 

 Status of the Pneumatic Treatment of 

 Respiratorv Diseases. Bv E. Darsvin 

 Hudson, Jr., M. D. 



Pneumatic Differentiation. Bv Herbert 



F. Williams, M. D. 

 Antiseptic Treatment of Pulmonary Dis- 

 eases by means of Pneumatic Differen- 

 tiation. ' By Herbert F. Williams, M. D. 

 Three pamphlets reprinted from The 

 Medical Record. 



The five pamphlets afford an excel- 

 lent siimmary of the theories and results 

 of pneumatic treatment of disease. 



Exchanges. 



[Exchanges are inserted in this column without 

 charge. They will be strictly limited to mounted ob- 

 jects, and material for mounting.] 



Wanted: Fine pc'^ns ,foraminifera, diatoms 

 (cleaned preferred), and all kinds of good material 

 for mounting. Lists exchanged and a full equivalent 

 given. M. A. BOOTH, 



Lorgmeadow, Mass. 



Wanted : Cleaned St. Vincent material, for cash. 

 E. A. SCHULTZE, 

 Tompkinsville, Staten Island, N. Y. 



For Exchange : Eyes of Limnlus, and leaves of 

 Deutzia scabra, rich and beautiful stellate hairs, 

 for finely mounted slides of diatoms or polycystina, 

 W. E. DAMON, 



Care of Tiffany & Co. , 



New York City. 



