382 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



intimately, and allowing coagulation to take place ; the resulting clot 

 carries clown the suspended particles and allows the clear fluid to be 

 decanted off. 



As the result of their numerous experiments with the filtrates of 

 various infective materials, e.g. brain emulsion, peritoneal fluid, faeces, 

 &c, the authors conclude that the specific micro-organism of rinderpest 

 is " invisible " — that it is too minute to be detected with any of the 

 present combinations of microscopical lenses, or to be demonstrated by 

 any known method of staining ; and further, that under ordinary con- 

 ditions the walls of the porcelain filter candle, Berkfeld 

 , or Chamberland, do not offer any resistance to its 



./ \ passage. 



\ The authors further suggest that this organism 



/ i habitually occurs within the bodies of the leucocytes, 



! <* and cite the observations of Kolle, who centrifugalised 



defibrinated virulent blood, and proved that whilst the 

 serum thus obtained was inactive, the deposit remained 

 virulent. 



Trocar for the Aseptic Collection of Portions of 

 Tumours.* — Dr. Cohn has devised what appears to be 

 an extremely useful instrument for the purpose of re- 

 moving portions of tumours, &c. for bacteriological 

 examination. 



It consists of a metal trocar and cannula (see fig. 94), 

 the former having a small cavity a with cutting edges, 

 excavated from the metal just above its point, the cavity 

 being concealed in the cannula e, which in turn carries 

 a movable disc b. The latter is clamped by the screw c, 

 to regulate the depth of penetration of the point of the 

 instrument. Sterilisation is easily effected either by 

 boiling or by hot air. In using the instrument the 

 point is plunged into the tumour, a half-turn of the 

 handle releases a small bayonet-catch d, running in a 

 slot in the cannula, and allows the point of the instru- 

 ment to be protruded beyond the end of the cannula 

 sufficiently to expose the cavity (as indicated by the 

 dotted lines), into which some of the tissue naturally 

 finds its way. Drawing back the handle of the instru- 

 Fig. 94. ment and returning the knob to its original position 



cuts off the enclosed piece of tissue, and at the same 

 time protects it from accidental contamination when the instrument is 

 finally removed from the tumour. 



Properties of Steel Castings.f — J. O.Arnold has undertaken re- 

 searches to ascertain the best standard composition for steel castings, 

 and gives, by way of instalment, the results of his examination of 

 nearly pure carbon-irons. Many specimens of such steels, as cast and 

 as annealed, were tested. He concludes that pure iron and carbon steel 

 is not a suitable material for fulfilling the modern specifications drafted 



* Centralbl. Bakt., l te Abt., xxx. (1901) pp. 625-6. 

 t Metallographist, v. (1902) pp. 2-24 (13 figs.). 



Cow*5 



