MICROPHYTES FOUND IN THE BLOOD. 357 



matter in a very clear light, and, being an authority of the first 

 rank, especially on the botanical phase of the subject which 

 forms the text of this paper, his statements on this particular 

 point are worthy of exceptional attention. The forms of plant- 

 life which have been recognised as having been more or less 

 closely associated with changes in living animal substances are 

 the lower kinds of fungi. These Nageli separates into three 

 groups : (1) Moulds^ characterised by branched, segmented, or 

 unsegmented filaments ; (2) Sprouting fungi, yeast cells of various 

 kinds, consisting of more or less oval corpuscles, which multiply 

 by means of sprouts from their surfaces ; and (3) Cleft-fungi or 

 Schizonif/cetes — minute spherical or oval bodies, which are multi- 

 plied by fission only, and which sometimes remain isolated, at 

 others form iinbranched rows (rods, threads, &c,), but only occa- 

 sionally present a cubiform aspect. To this group the bacterium, 

 vibrio, vibrio-bacillus, spirillum, &c., belong. 



Nageli writes : " I have separated the lower forms of fungi 

 into three groups. On account of many practical questions it is 

 of importance to know whether specific differences really exist, or 

 whether we have to do with the same species under different 

 conditions, it being possible that diff'erent fungi possessed a 

 'mould,' a 'sprout,'' or a 'cleft' form. This is a subject which 

 has formed the subject of debate during the last sixteen years, 

 and many observations have been recorded for the purpose of 

 showing that, as a result of cultivation experiments, the most 

 opposite forms have been seen to pass from one into the other.'' 

 With reference to this point Nageli forcibly points out the falla- 

 cies to which men are liable in drawing conclusions from cultiva- 

 tion experiments, and says that, in many respects, it would be as 

 rational for the husbandman to assert that the weeds in his field 

 were the result of transformations which the seed of wheat pre- 

 viously sown had undergone. No one would believe such a state- 

 ment, for the seeds of weeds are large enough to be easily recog- 

 nised, whereas the germs of fungi are of microscopic dimensions 

 — those of the schizomycetes often barely distinguishable with the 

 highest powers ; hence the assertions which have been made 

 regarding the transition of such minute organisms cannot easily 

 be controlled. " Moreover," adds Nageli, " the rapid and super- 

 ficial observer has a marked advantage ; the conclusions which he 

 has arrived at as the result of a so-called uncontaminated cul- 

 tivation \_Reinkultur'\ of a single week's duration may require 

 years of labour on the part of the thoroughly competent observer 

 to disprove." 



This question has of late years been investigated by many dis- 

 tinguished savants, notably by Professor de Bary, of Strasburg. 

 He has shown that a fungus undergoes but a very limited and 



VOL. XIX. NEW SER. A A 



