10 MORPHOLOGIC VARIATION 



haps be explained in part by the present day difficulty in obtaining 

 sufficient space in scientific journals for complete reports; but the 

 descriptions of observations offered do not give a hint of any wealth 

 of observation withheld from publication. The observations are for 

 the most part casual, not the result of systematically planned experi- 

 ments. Cultures are examined today and then set in the icebox for 

 weeks or months, at the end of which time they are found to have 

 undergone a transformation; but a systematic step by step observa- 

 tion of this transformation with a record of all the transitional stages 

 is lacking. Enderlein states in criticism of the monomorphists, "Der 

 methodische Hauptfehler war anfangs im Hinblick auf die Cyclo- 

 genie der Mangel einer methodische Beobachtung der Veranderungen 

 im Laufe der Zeit; meist wurde nur mit jungen Kulturen gearbeitet." 

 But if one substitutes "old" for "young" in this statement it applies 

 equally well to the pleomorphists. 



The failure to make continuous observation and record of all 

 stages of the transformations described is the most serious criticism 

 of the factual material in the work under discussion. It is due to 

 the technical difficulties involved ; but certainly much more could have 

 been done in this direction than has been recorded. It is only fair 

 to state that a certain amount of continuous microscopic observation 

 has been recorded: Hort (1917a) has illustrated the formation and 

 separation of buds and the formation of the intracellular structures 

 which he calls ascospores in meningococci, and the formation (1917b) 

 and later development into normal rods (1920) of buds in typhoid 

 bacilli; Almquist records the transformation of spherical conidia by 

 germination into a "probacterium" in typhoid bacilli; Enderlein 

 claims to have followed the fertilization of the "oit" by the "spermit" 

 in cultures of the cholera vibrio. Gardner has clearly observed the 

 origin of normal rods from branched cells, without, however, con- 

 cluding that they form part of a complex life cycle. But these iso- 

 lated cases only serve to emphasize the general lack of that continu- 

 ous step by step observation which must be made before any clear 

 idea of a life cycle can be established. It should also be stated in all 

 fairness that frequently it is impossible to tell from the author's 

 statement whether in particular cases he is recording hypothesis or 

 stating observed fact; statements of hypothesis are made so positively 



