246 SCIENCE PROGRESS. 



Klebs' book Die Bcdiugunocu dc7' Fortpfianzung bei 

 einigen Algen iiud Pilzen will have a peculiar value to all 

 botanists interested in Cryptogams and especially in Thal- 

 lophytes, and this in three connections. First, it is a record 

 of verv numerous and careful observations of the conditions 

 affecting the life of several types of fresh-water Alga;, and 

 of experiments pushed so far that it seems now possible to 

 be sure of growing these particular forms at will in the 

 laboratory by insisting on the maintenance of the condi- 

 tions. That this will be a boon to those who have hitherto 

 depended on accidental supplies of Algs from outside, 

 hurriedly collected and brought the day before into an en- 

 vironment which may be detrimental or not to these delicate 

 organisms, is obvious ; but it will also afford much help to 

 those who have had sufficient experience to know what Alga; 

 they can and what they cannot grow in the laboratory, and 

 must lead to extensions of power in this connection. 



Secondly, Klebs gives very clear directions for the 

 separation and pure culture of minute and intermixed 

 fresh-water Algae on solid media and in liquids, and it 

 should be a stimulus to many new departures when it is 

 known that these organisms can be treated in similar ways 

 to Fungi and Bacteria in this respect. True, we have 

 known for some time that something may be done towards 

 isolating pure cultures of Alga;, and Beyerinck and others 

 have given clear indications of success, but Klebs carries 

 this subject further than ever before, and shows how we 

 may look for rules of isolation and pure cultures of Algse 

 as trustworthy as those for other organisms. The appli- 

 cation of all this is obvious, but Klebs points the moral by 

 himself showino- that even observers so astute and able as 

 Woronin and Rostafinski confounded two organisms in 

 their celebrated study of Botrydiiini, and puts this so con- 

 vincingly that Strasburger has accepted and already repro- 

 duced the result in his recent edition of the Botanische 

 Practictun, just published. The criticism of those startling 

 observations which Choclat,^ Borzi and others have recently 



^ Chodat has replied to Klebs in a recent number of the Arch, des Sc. 

 Phys. et iVat de Geneve., t. iii., Jany. 1897. 



