466 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(6) Miscellaneous. 



Direct Enumeration of Bacteria in Water Samples.* — After a dis- 

 cussion of the investigations of previous workers, and of the theoretical 

 advantages possessed by direct enumeration methods over the ordinary 

 procedures, which involve the counting of colonies upon agar and 

 gelatin plates, Aumann describes his own experiences. In the author's 

 own researches, a Thomas-Zeiss cell was used at first, Ijut control 

 experiments with sterile saline and distilled water showed that such a 

 cell could not be rendered sufficiently sterile for these purposes. For 

 the remainder of the work, the author made use of a quartz chamber, 

 which could be sterilized. The cover-glass was also of quartz. The 

 apparatus rested upon a holder, which ensured that a horizontal position 

 was maintained. Comparative study of direct enumeration and of the 

 results obtained by plating, carried out with a large number of water- 

 samples, showed that direct methods were not reliable, and could only be 

 applied with safety to the examination of water containing a very large 

 number of organisms (more than 16,000). 



Pseudoparasitic Modifications in Structure of Erythrocytes.f 

 V. Schilling details the histological features presented by the normal red 

 cell when treated and examined by modern methods. These consist, 

 briefly, in a plate-like nucleus, in achromatic and central portions which 

 constitute the archoplasm, in the specific ha3moglobin portion and the 

 membranous sheath. The author then considers the various ap- 

 pearances found by various workers, who allege the existence of definite 

 parasites, such as chlamydozoa, associated with diseased conditions. He 

 submits that these are, in fact, not parasites, but pathological modifica- 

 tions of the various constituent elements of the cell, as above detailed. 

 He considers, in particular, Prowazek's cell-inclusions, Guarnieri l)odies, 

 Kurloff bodies, and so on, homologating them severally to portions of the 

 archoplasm. 



Carazzi, D., & G.Levi — Tecnica microscopica. 



Milauo : Soc. editr. libr., 2nd. ed., viii and 500 pp. 



Metallography, etc. 



Structure of Products obtained in Manufacture of Lead. J — G. von 

 Komorowski describes and illustrates the microstructure of 22 specimens 

 of matte lead of various degrees of purity, etc. 



Metallographical Laboratories. §— A good description is given of 

 the metallographical laboratories in the new Metallurgical Institute of 

 the Technical High School, Breslau. Three types of Microscope are 

 used — a Martens stand by Zeiss, an apparatus by Reichert on the Le 

 Oh atelier principle, and a Guertler apparatus by Leitz. The Reichert 

 model includes the very convenient reflex camera. Krupp's laboratories 

 and metallographical apparatus are also described. 1| 



* Centralbl. Bakt., 2te Abt., xxxiii. (1912) pp. 624-35. 



t Centralbl. Bakt., Ite Abt. Orig., Ixiii. (1912) pp. 393-400. 



+ Metallurgie, viii. (1911) pp. 741-2 (28 figs.). 



§ Stabl und Eisen, xxxi (1911) pp. 1565-79 (12 figs.). 



II Stahl und Eisen, xxxi. (1911) pp. 1624-30 (11 figs.). 



