166 The Philippine Journal of Science ms 



or insoluble, is by itself more or less viable and may be capable, 

 to a certain extent at least and under certain conditions, of 

 persisting as such and even of increasing or growing. 



The hypothetical substance or body (to designate which the 

 term "cryptoplasm" seems appropriate), though it may play a 

 more or less important part in the pathogenic expression of the 

 infection, is probably in some cases dependent upon the presence 

 of the original differentiated parasitic element for its continuous 

 replacement and thus for its perpetuation in the lesion, in which 

 case it would be successfully resisted by the host in the absence 

 of the formed element. In other cases, however, it may be able 

 to perpetuate itself and maintain the lesion. Reversion to the 

 differentiated parasitic form may be possible in some cases, 

 under proper conditions; in other cases, and under ordinary 

 conditions, it probably does not occur. 



There is evidence that the cryptoplasm is, or may become, 

 intraleucocytic and that, though morphologically indefinable from 

 the protoplasm of the host cell, it may there exert special in- 

 fluences, producing special results, and may sometimes even be 

 indirectly demonstrable therein by cultural methods as a formed, 

 though not necessarily as a specifically differentiated element. 



Such a substance, it is evident, might sometimes be of greater 

 immediate importance from the viewpoint of pathogenicity than 

 its formed generator. Should it replace the latter entirely in 

 a progressive lesion, efforts to demonstrate or isolate the causa- 

 tive agent of that lesion by usual methods would of necessity fail. 

 Under such conditions the postulates of Koch would be impos- 

 sible of fulfillment, since these are based on the essential sim- 

 plicity of pathogenic organisms and of their modus operandi, on 

 the integrity of form of the invading organism, on its persistence 

 during parasitism and final recoverability in cultures as such, 

 and on the suitability or adaptability of the organism as such to 

 both parasitic and saprophytic life. 



The above hypothesis is based on the results of but two years' 

 work and, no doubt, will be more or less modified by future 

 studies. As stated, it has been constructed to cover a group of 

 more or less clear-cut observations. Though much of it cannot 

 as yet be proved, it is what appeals to me as the more conser- 

 vative of two possible interpretations, the other of which will 

 not be discussed at this point. 



INTRODUCTION 



In the present report it is desired to describe particularly 

 certain features observed in the course of a cultural study of 



