258 THE AMERICAN MONTHLY [JSTovember, I 



(o. I per cent.) solution of chromic acid. Borax-carmine and picro- 

 carmine were chiefl}' used for staining. Sometimes a whole colony 

 was imbedded. 



The development of the polypide within the statoblast was thus 

 studied : a statoblast was hardened in alcohol, and its edge was then cut 

 between two pieces of elder-pith so as to make an opening in the chiti- 

 nous shell ; it was then stained and kept in alcohol until cut. In cut- 

 ting the statoblast celloidin was indispensable, owing to the hardness 

 of the shell. Fresh specimens were put on a slide after stupefying with 

 cocain. The habits of the colonies may be studied by keeping them in 

 vessels through which water is always flowing. — your. Coll. of Scl. 

 Imper. Univ. yapan., l8gi. 



Remarks on a new method (Interlamellar Films) of study- 

 ing the Development of Micro-Organisms and the Mutability of 

 their Characters and Properties — Sheridan-Delepine considers 

 the simplest way of solving the vexed question of the constancy or of 

 the mutability of pathogenic bacteria to be in the isolation of one spore, 

 and the following of its development through all its stages and in dif- 

 ferent media. Having failed by the dilution method of Bi-efeld and 

 by the plate and drop cultivation to obtain the desired results, the au- 

 thor was led to adopt a new mode of cultivation, which, while by no 

 means perfect, has yielded ^me satisfactory results. The principle of 

 the method is to inclose a thin layer of the nutrient medium between 

 two parallel plates, so as to force the organism to grow in definite di- 

 rections. If evaporation be prevented, the effects of capillarity are 

 such that the most fluid media becomes fixed and can be used. At each 

 end of a glass slide (i^ in. by 3 in.) a narrow strip of glass is fixed so 

 that the slides can be piled one upon the other in the incubator, or in- 

 verted on a sterilized plate. Upon the upper surface of the heated slide • 

 three small drops of sealing-wax are dropped. These drops are used 

 to support a cover-glass an inch and a quarter in diameter at a certain 

 distance above the slide. The slide being sterilized, a drop of nutrient 

 fluid is placed upon it, and the slide inverted or placed under a thoroughly 

 sterilized plate. The cover-glass is then sterilized, and the surface 

 which is to be next to the slide is carefully protected from the access of 

 any germ or dust. On this surface a very small drop of sterilized ma- 

 terial is placed, and this drop is touched with a wire charged with a 

 few organisms. A number of cover-glasses are thus prepared and ex- 

 amined with a pretty high power, the inoculated surface being placed 

 downwards. When a slide is found containing the number or kind of 

 organism desired, it is gently placed over the drop of nutrient material 

 on the slide. A heated rod is then applied successively over the three 

 drops of sealing-wax until the inoculated fluid has spread evenly and to 

 the thickness required. The slides are then transferred to a moist 

 chamber in an incubator. Slides thus prepared can be studied at pleas- 

 ure. Delepine has followed the development of bacteria and spores of 

 pathogenic pyrenomycetes for days and weeks. By this inteidamellar 

 method the branching of the schizomycetes, and even the formation of 

 oxalic acid out of gelatine, starch, gum-arabic, and possibly cellulose, 

 can be demonstrated. The formation of oxalic acid only begins when 

 growing filaments have free access to air. Further details regarding 

 the modifications which have been suggested by circumstances and the 



