1884^1 



MICKOSCOPICAL JOURNAL. 



91 



regulation of temperature is neces- 

 sary, and for this purpose the ther- 

 mostat of Arsonval is used, which 

 allows of a constant heat to ^^ of a 

 degree ctentigrade. The culture of 

 the bacillus of tuberculosis has been 

 so made, and in the same way the 

 bacillus of glanders, of osteomyelitis, 

 the microbia of the septecajmia of the 

 rabbit, of the turkey, etc., etc. 



'Much laboratory work has been 

 done in the bacteriscopic examination 

 of the air, the water, and the soil. 

 To examine the air of an apartment, 

 it is simply necessary to expose ster- 

 ilized slices of potato upon which the 

 germs fall and colonize themselves. 

 For water, a weak solution of gela- 

 tine, with the necessary nutrient salts, 

 is mixed with a small proportion of 

 the water, left to the surroinuling 

 temperature, and in a little time the 

 solidified gelatine shows whitish or 

 grayish granules, which the micro- 

 scope resolves into colonies of special 

 germs. To estimate the pnjpcjrtional 

 quantity of these germs, the contami- 

 nated gelatine is spread out on a huge 

 plate of glass over paper that has 

 been rided and counter-ruled so that 

 a rapid and satisfactory count of the 

 islets of microbian vegetation can be 

 made. Thus are to be seen the frac- 

 tions of a drop of the water from the 

 canals of Berlin, of pump water of 

 the public foimtains, of sewer water, 

 and of the water of the river Spr^e, 

 above and below Berlin, these last 

 demonstrating in a striking manner 

 how water becomes contaminated, 

 and how it purifies itself by nature's 

 processes. Nothing is more curious 

 than to examine these plates covered 

 with little clods of turf, islets of dust, 

 white, green, and brown spots, little 

 collections of pearls, and a crowd of 

 special forms, so diverse as to appear 

 like a public park or garden in min- 

 iature. As in all the other analyses, 

 each variety of vegetation, after being 

 carefully examined by the micro- 

 scope to ascertain its purity from all 

 foreign mixture, receives an isolated 

 culture with tiie most diverse sub- 



stances, in turn submitted to its in- 

 fluence. 



'3d. Finally comes the reproduc- 

 tion of the original disease by the aid 

 of the artificially developed germs. 

 This has definitely proven for the mi- 

 crobia of charbon by Pasteiu", of tu- 

 bercle by Koch, and for the bacteria 

 of glamlers, the coccus of erysipelas, 

 etc. The pavilion displays numerous 

 anatomical specimens from rabbits, 

 dogs, and other animals that have 

 been inoculated with the bacteria of 

 tubercidosis, cultivated to the tenth, 

 twentieth, and higher generations, 

 and which demonstrate positively the 

 presence of tubercles in the diflerent 

 organs. Other specimens show the 

 inoculation of the cultivated bacteria 

 of glanders on the rabbit and on the 

 horse. The nasal mucous membrane 

 and the idcei'ated ears so exhibited 

 give the most positive evidence of 

 this infection. A group of photo- 

 graphs on glass completes the series 

 of objects exhibited. These direct 

 reproductions of the different varie- 

 ties of the known pathogenetic infe- 

 rior organisms, as well as the disj^o- 

 sition they affect in the diseased or- 

 gans, are for the most part, in spite 

 of the often enormous enlargement 

 which they have imdergone. of an 

 absolute sharpness and admirable pre- 

 cision of detail.' 



Microscopical Tcchiiic. 



IV. MOUNTING OBJECTS DRV, CON- 

 TINUED. 



We have now to describe the 

 method of mounting objects that re- 

 quire deep cells. Such objects being 

 opaque may always be mounted in 

 cells with opaque bottoms. The bot- 

 toms of the cells may be made with 

 either of the materials mentioned on 

 page 74, or dead-black paper may be 

 used cut to fit the cell and held in 

 place by mucilage. The cells may 

 be formed in various ways, but the 

 method that has proved most conve- 

 nient and satisfactory in our hands is 

 one that has been roundly criticised 



