136 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(6) Miscellaneous. 



Method for Ascertaining Frequency of Pathogenic Microbes in 

 Air.* — Dr. E. Concornotti exposed glycerin-agar surfaces in Petri's cap- 

 sules for different lengths of time to the air in various places and spaces. 

 The capsules were then incubated for 24 hours at 37°. Sterilised water 

 was then run over the plate, so as to obtain an emulsion of microbes. 

 Some of this emulsion was examined microscopically in order to obtain 

 a rough estimate of the kinds of organism present. With other portions 

 rabbits were intravenously and intraperitoneally infected. The intra- 

 venous method was very successful in discovering pathogenic germs, 

 and seems especially suitable when their virulence has been lowered. 

 Pathogenic bacteria were most frequent in, or in the vicinity of dirty 

 places, and their order of frequency was found to be Staphylococcus 

 pyogenes 'aureus, St. pyogenes alius, Bacillus coli communis, Diplococcus 

 pneumoniae. 



Apparatuslfor rapidly Disintegrating Micro-organisms. |— Mr. S. 

 Rowland describes an apparatus for obtaining the cell-contents of micro- 

 organisms. A mass of the organisms together with quartz sand and steel 



Fig. 87. 



balls are placed inside the steel tube A (fig. 37), which is closed at both 

 ends and rigidly fixed to the aluminium frame B. The frame is caused to 

 oscillate horizontally by means of the rod G and the crank-pin H. Two 

 steel rods E, E' support B, and parallel motion is allowed by means of the 

 joints Q, E, P, 0. C is a steel Irame clamped to the table by D. Motion 

 is given to the crank-wheel S by the cord K, driven by an electro-motor. 

 The axle of S runs in bearings supported in the frame J, and carries a 

 fly-wheel I. The frame J swings about the stud^L, carried in a pair 

 of angle-pieces M, and bolted to the table by N. This arrangement 

 allows easy adjustment of the cord K for tension. At 3500 revolu- 

 tions a minute, tubercle bacilli are disintegrated in 10 minutes. 



Contact Negatives for the Comparative Study of Woods.J — Mr. 

 R. A. Robertson describes how he gets large sections of woods on a 



* Centralbl. Bukt. u. Par., 1" Abt, xxvi. (1899) pp. 492-501 (2 figs.). 



t Trans. Jenner (late British) Inst. Prev. Med., ser. ii. (1899) pp. 250-1 (1 iig.)- 



J Trans, and Proc. Bot. Soc. Edin.. xxi. (1899) pp. 162-5 (1 pi.). 



