106 SUMMARY OP OURBENT RESEARCHES RELATING TO 



Algophag^a pyriformis.* — Prof, N. Sorokin describes an organism 

 which he first discovered in 1886 in its monad form. Since then he 

 has observed the various phases of its development. In the free- 

 swimming stage it occurs as small colourless monad-like bodies, which 

 move slowly forward by the aid of cilia. These corpuscles consist of 

 two parts — a head and long processes. The head is oval or pyriform, 

 and is from 2 to 4 /x. long. These bodies are termed small swimmers, 

 in contradistinction to larger bodies of similar appearance, which are 

 developed from a combination or melting together of two or more small 

 ones. Both kinds seem, from the illustration, to be very much alike, and 

 to nourish themselves by sucking at unicellular algae. After sucking at 

 the alga the swimmer loses the pseudopodia, and forms a microcyst, 

 which is apparently a quiescent condition, during which the absorbed 

 chlorophyll is digested. 



Another condition in which this organism appears is as a macrocyst. 

 In this state the pseudopodia are withdrawn, and a transparent mem- 

 brane envelopes the whole body, just as has happened with the microcyst. 

 The only difference appears to be in the size, the macrocysts being 

 four or five times larger than the microcysts. When the membrane 

 has been formed, vacuoles, oil-drops, and nuclei appear within the 

 macrocysts. Next the vacuoles disappear, the oil-globules crowd 

 together, and the bottom of the cell is filled with a green mass. As 

 time goes on — a question of a few hours — further changes occur within 

 the cell-contents, spherules appear, the cell bulges at one end, and then 

 having burst owing to the pressure, gives exit to a number of small free 

 swimmers with pear-shaped heads and long pseudopodia usually three 

 in number. 



The author was fortunate enough to observe a resting form of this 

 organism, which was not distinguishable from the zygosperms of fungi. 

 From the text and illustration it would seem that two separate organisms 

 were concerned in this phase. 



SarcinsB of Fermentationf. — Dr. P.Lindner describes eight varieties 

 of Sarcina which he has found in beer, mash, and in the air and water 

 of breweries. 



Pediococcus cerevisise Baleke is a bacterium which occurs as a mono-, 

 diplo- or tetracoccus. It was first described by Pasteur, and has been 

 found to be one of the principal causes of the clouding of beer. It grows 

 well on the usual media, and its most marked characteristic is that it 

 will not bear being transferred from alkaline to acid media, but does 

 from acid to alkaline. It will not grow in sterilized beer. Cultivated 

 on potato it produces involution forms like Bacterium aceti and B. termo. 

 It is killed in eight minutes by a temperature of 60° C. 



Pediococcus acidi lactici. As its name implies it produces an acidity 

 of the media on which it is cultivated (neutral malt extract solution at 

 41° C.) The acid solution replies to tests for lactic acid. The sarcina 

 is found to be identical with the organism which plays an important 

 part in fermentation, and which is known by the name of " Kugelbac- 

 terium." It developes best at a temperature of 41° C. ; is killed in five 

 minutes at 62° C, and in 20 minutes at 56° C. It appears to thrive 

 better in the absence of air. 



* Centralbl. f. Bakteriol. u. Paiasitenk., iv. (1888) pp. 419-27 (1 pi.). 



t Inaug. Diss., 1888, 58 pp. (1 pi.). Cf. Bot. Centralbl., xxxvi. (1888) pp. 97-100, 



