OF THE PHYTOZOA. 187 



The growth of the mucous balls is the consequence of the constantly re- 

 peated transverse fission of the Bacterium-hodies, and is exceedingly raj)id. 

 Yon Flotow seems to have detected the compoimd masses, and named one 

 such Microhaloa teres ; but Cohn finds it necessary to create a new genus, 

 which he has named Zooglma. 



Of the remaining Vibrios, Cohn has not as yet complete researches ; yet he 

 finds sufficient support from analogy to warrant him in assuming a like history 

 for them as for ZooyJoea. The larger forms of Vibrio have (he says) a striking 

 affinity with the OsciUarice, whilst the longer, slowly-moving species have a 

 very great likeness to the shorter fibres of Hyyrocrocis, from which, some have 

 stated, Vibrios derived their origin. The affinity of Vihyno with the colour- 

 less OsciUarice — mth the genus Beggiatoa, in which also very delicate forms 

 occiu' — may be especially pointed out ; but this affinity is yet more striking 

 with SpiriUmn and Spirocliceta, the other two genera of Vibrioma. Fiu-ther, 

 in Oscillarieae we meet with straight species, e. g. OsciUaria, and spirally 

 convoluted forms, e. g. Spirulina, just as we have straight forms in Vibrio, 

 and spirally-tmsted ones in Spirillum and Sjnrochceta. Likewise, on com- 

 paring the movements of Spirochceta w^th those of Spirulina, we find no dis- 

 tinction between them except in energy and livehness. 



The results of his examination of Vibrionia are thus summarily stated by 

 Cohn (p. 130) :— 



"1. The Vibrionia apparently all belong to the vegetable kingdom ; for they 

 •exhibit an intimate affinity with undoubted Algae. 



" 2. By reason of their want of colour, and their occiu-rence in decomposing 

 infusions, the Vibrionia belong to the group of aquatic fungi {MijcopJiycece)^ 

 Cohn, however, shows good reason for not admitting this as a natiu'al group 

 distinct from Algge. 



" 3. Bacterium Termo is the motile swarming-phase of a genus, Zooglcea, 

 allied with Palmella and Tetraspora. 



" 4. Spirochceta plicatilis belongs to the genus Spirulina, of which it must 

 be at once admitted as a species (^Spirulina plicatilis). 



"5. The long Vibrios which do not coil (Vibrio Bacillus) arrange them- 

 selves Avith the more delicate forms of Beggiatoa (OsciUaria). 



^' 6. The shorter Vibrios and SpiriUce resemble indeed, in form and charac- 

 ter of motion, the OsciUarice and Spiruliyice ; nevertheless I cannot positively 

 decide on their true natui'e." 



To this abstract of Cohn's paper on Vibrionia we must add a notice of 

 Dr. Burnett's essay, which is equally in favour of their plant-Hke natui'e. 

 The chief observations and opinions of Dr. Burnett are — that a branching of 

 the chains, similar to that of the ordinary forms of Algae, is observable in 

 Vibrionia, particularly in Spirillum; that, on watching their gradual growth, 

 the smaller seem no other than the younger forms of larger species (for in- 

 stance, that Vibrio is the first condition under which Bacterium and Sp>i- 

 rillmn appear) ; thaf besides self-di\ision, propagation is effected by budding, 

 a fact fu]-ther exemplified by the occuiTcnce of ramifications ; and that in 

 yoimg forms a nucleus is absent, although one becomes apparent in advanced 

 stages. Again, as to the movements of Vibrionia, Dr. Biu-nett can see no 

 fiu'ther indication of movement in them than in spermatozoa and in vegetable 

 cells, like which they are imaffected by electrical shocks, which are fatal to 

 the lower forms of animal life. 



'' Their cell- structure and their vital (not voluntary) motion would then 

 lead us to infer that the Vibrionia are Algous plants, and not animals. This 

 throws light on several common phenomena. One in particular is, that the 

 Vibrionia should almost invariably be found in infusions and liquids that 



