Apeil 1, 1910] 



SCIENCE 



501 



etc. In all this Fraeastorius shows himself to 

 be a highly original thinker, far in advance 

 of the pathological knowledge of his time, 

 ■which was mainly reducible to the old Hippo- 

 cratic doctrine of disease as a corruption of 

 the humors of the body. But it is in his re- 

 markable account of the true nature of disease 

 germs, or seminaria contagionum, as he calls 

 them, that we find him towering above his 

 contemporaries. He seems, by some remark- 

 able power of divination or clairvoyance, to 

 have seen morbid processes in terms of bac- 

 teriology more than a hundred years before 

 Kircher, Leeuwenhoek and the other men who 

 worked with magaifying glass or microscope. 

 These germs he describes as particles too small 

 to be apprehended by our senses (particulce illcs 

 insensibiles) , but which, in appropriate media, 

 are capable of reproduction and thus of infect- 

 ing the surrounding tissues {prima enim semi- 

 naria, quce adhceserunt e vicinis humoribus 

 ad quos hahent analogiam consimilia sihi alia 

 generant et propagant, et hoec alia donee iota 

 humorum massa et moles afficiuntur). These 

 pathogenic units Fracastorius clearly surmises 

 to be of the nature of colloidal systems, for if 

 they were not viscous or glutinous by nature, 

 he holds, they could not be transmitted by 

 fomites (cujus signum est, quod quwcunque 

 per femitem, afficiunt omnia lenta glutino- 

 saque conspiciuniur) ; while germs trans- 

 mitting disease at a distance must be able to 

 live in the air a certain length of time (non 

 solum in fomite sed in aere per certum tempus 

 servari), and this condition is only possible 

 when the germs are gelatinous or colloidal 

 systems ; for only hard, inert, discrete particles 

 could endure longer (sed eerie, quw lenta sunt 

 et glutinosa, quamquam parvissima sint, pos- 

 sunt quidem si non omnino tantum quantum 

 dura, vivere, at paulo minus possunt). These 

 colloidal particles have the power of resisting 

 forces of small magnitude, but can not resist 

 such agencies as extremes of heat or cold, 

 which reduce them to phases of dissipated 

 energy (non solum dura, sed et lenta sese de- 

 fendunt ah alteraiionihus multis, si mediocres 

 sint, magnas autem non ferunt: propter quod 

 et ah igne ahsumuntur seminaria omnium, 



contagionum, et ah aqua etiam frigidissima 

 franguntur). Finally Fracastorius conceives 

 that the germs become pathogenic through the 

 action of animal heat (et ipsa aciu fiunt a 

 calore animalis), and that in order to produce 

 disease it is not necessary for them to undergo 

 dissolution, but only metabolic change (quan- 

 tum quidem sufficit ad putref actionem facien- 

 dam, non necesse esse corrumpi particulas 

 ipsas, sed alterari solum . . . nihil tamen 

 prohibet et corrumpi etiam, sed non necesse 

 est, quaienus aiiinet ad faciendum putrefac- 

 tionem). Thus Fracastorius seems to have 

 had a clear notion (or prevision) of the causa- 

 tion of disease by microorganisms, and he ap- 

 pears to have seen these organisms as made up 

 of those gelatinous or " dispersed " systems 

 which modem physical chemists call colloidal 

 states of substance. The agreement of his 

 imaginative hypothesis with the physico- 

 chemical view-point is little short of wonder- 

 ful, when we consider that he had no micro- 

 scope nor other instrument of precision save 

 his own mind. 



In referring to the organisms seen by 

 Kircher, Dr. Eiley asserts that he must have 

 seen " the larger species of bacteria " long 

 before Leeuwenhoek's discovery. But neither 

 Kircher nor Leeuwenhoek could have seen 

 bacteria of any kind with the lenses at their 

 command, although the latter undoubtedly 

 saw various animalculae, diatoms, blood cor- 

 puscles and the finer anatomy of the tissues. 

 According to Miiller and Prausnitz,° Kircher 

 saw in the blood of plague patients " a count- 

 less brood of worms not perceptible to the 

 naked eye," and he was not staggered by the 

 fact that these " worms " could also be found 

 in healthy blood. The explanation is simple. 

 His glass or microscope was only 32-power at 

 best, and the worms he thought he saw were 

 (as in Malpighi's case) simply rouleaux of red 

 blood corpuscles. 



To sum up, over one hundred years before 

 Kircher, Fracastorius gave the first definite 

 statement of the true nature of infection by 

 disease germs; Kircher then boldly restated 



- " Handbuoli der Geschichte der Medizin," Jena, 

 1905, IT., 805. 



