^6 Synopsis of the Bacteria and. Yeast Fungi. 



over, Van Tieghem and Engelmann describe (see infra, p. 88) 

 bacterioid forms containing chlorophyll, and the resemblance 

 between Beggiatoa and Oscillaria, both in form and in the 

 characteristic oscillating movement, is so great that some 

 botanists do not yet separate them. Again, Leuc^nostoc 

 differs from Nostoc solely in the want of chlorophyll, the 

 very peculiar formation of the spores being alike in both. 

 Compare also Cohnia with Clathrocystis. The two kinds 

 evidently form two parallel series, which may conveniently 

 be united under the name of Schizophyta, being called 

 Schizophycese and Schizomycetes respectively. They are, 

 nevertheless, physiologically so distinct that there are 

 decided objections to interweaving them in one series, as 

 Cohn proposed. It would seem to be proved that, in all 

 cases where oxygen is given off during vegetable growth, 

 chlorophyll is present; Rostafinski at one time believed 

 that Haematococcus dissociated carbonic anhydride without 

 chlorophyll, but it is now known to be present in that Alga, 

 though masked by the red colouring matter. 



There may, perhaps, be detected, in the recent spread 

 of Zopf's views upon the pleomorphy of the Bacteria, a 

 little of that rage for "following the fashion," which is 

 almost as rife among scientific men as in the outer world. 

 A review of what has taken place in similar cases before 

 will teach the necessity of caution. When the swarm-spores 

 of Algae were first discovered, it was prophesied by Siebold 

 that most of the green moving Infusoria, described by 

 Ehrenberg, would be found to be only similar stages of 

 other algal forms. But this prophecy has not been fulfilled. 

 Again, when the doctrine of the pleomorphy of the Muco- 

 rini was first started by De Bary, it was eagerly seized upon 

 and its scope rapidly extended by rash observers, until in 

 the writings of some authors there was a confusion of species 



