108 PROTISTS AND DISEASE 



classification. The group to which the causal parasite of 

 molluscum belongs has not as yet, perhaps, been adequately 

 introduced to cryptogamic botanists. 



The Molluscum Body is not a Symbiotic Cell. Arguing 

 from the fact that a 1 in 10,000 suspension of a ground-up 

 molluscum tumour gives a virulent filtrate, and that when 

 stained by Giemsa's method the molluscum body shows a 

 certain minute structure M. Borrel concludes that this body 

 is the result of symbiosis between an invisible microbe and 

 an epidermal cell. The observations recorded above of the 

 behaviour of molluscum bodies in water- cultures negative 

 this idea. 



Microhenads. The word microhenad I suggest as the 

 designation for the phase in which the filtrable micro- 

 organisms are at the time they can be pressed or aspirated 

 through a filter that arrests bacteria. This suggestion is 

 made on the supposition that the " filter-passers " have 

 not yet been named in biology. The word is made from the 

 Greek ei/as, a unit. 



It is not needful to give here the already long and growing 

 list of organisms that have been found to have a microhenad 

 phase or phases ; the details of the technique of filtration as 

 used for molluscum virus is given below, p. 117. 



The Kinds of Filter used for Virus-filtration. Besson lays 

 down that too fine a filter must not be used ; a Berkefeld ' V,' 

 or a Chamberland ' F.' The former is made from infusorial 

 soil and hence is composed largely of silicious skeletons of 



