1884.] 



MICKOSCOPICAL JOURNAL. 



187 



procedure of obtaining a pure culture 

 from one preceding. When the source 

 of the bacteria is an exudate, or the 

 flow of the animal body, various 

 methods are in use. The method 

 above given may, however, be em- 

 ployed in most cases. 



The success of the work depends 

 as much upon the worker as upon 

 the apparatus employed. A bun- 

 gling manipulation may cause failure 

 with the best method. The pei'sonal 

 equation in this as in many other 

 fields of reseaixh is necessarily an 

 important factor. Many minute de- 

 tails, which may seem too trivial to 

 be mentioned, are slowly acquired, 

 and gradually help to increase the 

 percentage of absolute success. 



It is evident that the reservoir may 

 be variously modified. A flask- 

 shaped body may be used for cul- 

 tures that require an abundance of 

 air, but the test-tube form will serve 

 nearly all purposes. It enables the 

 nature of the opacity in the liquid to 

 be readily determined, while the ear- 

 liest traces of a membrane or a de- 

 posit are more easily detected than 

 wath a broad body and a flat bottom. 

 The microscopic appearance of these 

 features, in case of many forms, will 

 enable the experienced observer to 

 foretell whether the culture is pure or 

 contaminated. 



The culture-tube, then, recom- 

 mends itself as a simple, very neat 

 apparatus, readily filled, sterilised, 

 and inoculated. It dispenses with 

 the troublesome and dangerous expe- 

 dients of disturbing cotton plugs, and 

 of tying down various air-filtering 

 materials. It is easily cleaned, and 

 hence may be used over and over 

 again, the original cost of the tube 

 being in this way reduced to a mini- 

 mum in the end. It does not break 

 readily, nor are there any sharp or 

 jagged edges to be feared in the ma- 

 nipulation of dangerous cultures. It 

 is very compact, and occupies but 

 very little space in a thermostat. 

 Finally, the chances of contamination 

 through the air during the process of 



inoculation are practically of no ac- 

 count. We have not yet seen an im- 

 pure culture derived from a preced- 

 ing pure culture during the period of 

 our experience with these tubes. It 

 is becoming more and more the con- 

 viction of careful investigators — and 

 Brefeld, in describing his method, 

 emphasizes it — that in a room where 

 dust is carefully managed a short ex- 

 posure to the air is not dangerous. 

 The utensils used, upon which parti- 

 cles are continually being deposited, 

 unless thoroughly sterilised, are the 

 chief carriers of a miscellaneous con- 

 tamination. 



Histology of Lingula.* 



BY H. G. BEYER, SURGEON, U. S. N. 



It was only after considerable hesi- 

 tation that I finally concluded, in a 

 conversation with our esteemed sec- 

 retary, Mr. Hitchcock, a few days 

 ago, to venture making a few remarks 

 on this subject, the pressure of my 

 legitimate duties as naval medical 

 officer having frequently interrupted 

 my studies, and preventing me from 

 presenting a more complete account, 

 at least at present. I will, therefore, 

 confine my remarks on those most 

 interesting little organs called hearts, 

 or oviducts, or also segmental organs. 

 These organs have attracted no little 

 attention and interest on the part of 

 the most distinguished anatomists 

 ever since the time they first turned 

 their attention to the study of the 

 anatomy of the brachiopods in gen- 

 eral. 



Before the time when Hancock 

 wrote his classical essay on the or- 

 ganization of the brachiopoda in the 

 Phil. Trans, of 1858, these organs 

 had been described as hearts. Mr. 

 Hancock, in the article referred to, 

 says : ' Four years ago I had occa- 

 sion to dissect Woldhetmla Australis^ 

 Terebratulifia caput serpentis^ and 

 Lingula anoiina^ and was then 

 struck with the peculiar appearance 



Abstract. Read before Section G, A. A. A. S. 



