soo 
SUMMARY OF CURRENT RESEARCHES RELATINO TO 
tlie sterilization of cultivation media, which is impracticable by means 
of heat, is the main topic. 
Pseudomicrobes of Normal and Pathological Blood.* — Herr Koll- 
man, in alluding to the appearances observable under normal and patho- 
logical conditions in human and animal blood, remarks that they are 
easily mistaken for micro-organisms, and points out that the works of 
numerous writers, especially those on anaemia and malaria, teem with 
examples of this confusion. 
According to the author, the following are the chief forms the 
pseudomicrobes may assume : — (1) simple spherical forms measuring 
0 • 5 fx or less ; (2) large spherical and oval ; (3) small and large rodlets ; 
(4) various combinations of the foregoing elements ; (5) a peculiar form 
resembling a dumb-bell. 
As a rule, all are mobile, often extremely so, and their movements 
have very often the appearance of being voluntary. 
According to the author these forms are for the most part nothing 
else than degeneration derivatives of the red discs, while some of them 
originate from leucocytes, the blood-plates not being concerned in their 
formation. 
Cultivations in fluid media give deceptive appearances, while on solid 
no development occurs. 
Photogenic and Plastic Nutriment of Luminous Bacteria.j — That 
“ photogenic aliment ” is intended to apply to the light-giving quality 
of the nutrient medium is easy to understand, but without a special 
definition the comprehension of the term “ plastic nutriment ” would be 
difficult. When the nutriment is suitable for vegetation and reproduc- 
tion, its action is not confined to producing merely luminous phenomena, 
but it gives rise to “ auxanogrammes,” or fields of increase, characterized 
by the numberless colonies which lie within the diffusion area of the 
nutrient substance and developed much more strongly than outside. 
When this condition exists the aliment is said by Prof. M. W. 
Beyerinck to be plastic. 
Although the author’s remarks are scattered over a large area, 
some of them are interesting, and the practical part may be summarized 
very shortly. The increase and emission of light by photogenic bacteria 
was found to be dependent on the association of pepton with certain 
nitrogenous and non-nitrogenous bodies by which the requisite nitrogen 
and carbon were obtained ; for example, with pepton, asparagin, or 
glycerin alone there was darkness or no increase, but in combination 
both light and increase. 
This group is called pepton-carbon bacteria. Another group is 
characterized by the faculty of peptonizing proteids by means of 
their proteolytic enzyme. This is the pepton group, of which Photo- 
bacteria luminosum et indicum are examples, while the first group 
includes Photobacteria phosphor escens et Pflugeri. 
After discussing the theory of the luminous function at great length, 
and then its biological significance, the author passes in review the 
relations of photogenic bacteria and certain enzymes, not the least 
* Centralbl. f. Bakteriol. u. Parasitenk., ix. (1891) p. 839. 
t Archiv. Neerlandaises Sci. Exact, ct Nat., xxiv. (1891) pp. 369-442. 
