SMALL-POX AND VACCINIA 47 



hours after vaccination. That was, I believe, the first demonstration 

 of Guarnieri's bodies in the amoeboid phase. This same amoeboid 

 phase occurs also at a certain stage of small-pox lesions. They are 

 very clearly shown in a specimen given to me by Professor Calkins 

 in 1903. 



Some of the intracellular bodies, and more of those that have 

 escaped into the intercellular spaces e.g., Fig. 12, a and b owing 

 to breaking-down of the host-cells, contained chromatin in various 

 forms. These free bodies, like Guarnieri's corpuscles, were dis- 

 tinguishable from the tissue and other cells of the host by a 

 higher refraction and differences of staining, and by careful com- 

 parison I was led to recognise that the series of forms could not well 

 be anything but stages in the life-history of a protozoon. 



In order to obtain free bodies, such as those shown in Fig. 12 at a 

 and b, etc., the greatest care is required, and many sections must be cut. 

 When a suitable specimen has been obtained, there are peculiarities 

 of optical quality and staining reactions that distinguish the Guarnieri 

 bodies from tissue-cells, and the forms I described as parasites, in 

 which chromatin had appeared, are linked to the ordinary Guarnieri 

 bodies by retaining in part those same features which differentiate 

 them from the normal elements of the tissues. In my original 

 article, referred to above, a series of such nucleated forms are repre- 

 sented. They are probably the same bodies subsequently described 

 by Funk and De Korte. The important observations of these authors 

 will be again referred to below. It has been said that the small 

 Guarnieri body has the staining reaction of chromatin. I think 

 this is hardly correct. In well-differentiated preparations stained 

 with acid haematoxylin and eosin the nuclear chromatin of the 

 corneal cells show the pure deep blue colour of chromatin, whilst 

 the Guarnieri bodies are of a purplish tint, having apparently 

 retained the two stains about equally. 



In 1897 Wasielewski 1 advanced the subject materially. He 

 showed that no kind of injury to the cornea, nor inoculations with 



1 Wasielewski, 'Ueb. die Form und Farbbarkeit der Celleinschlusse bei 

 Vaccineimpfungen,' Cent, fur BakL, xxi., s. 901, and Zeit. fiir Hygiene, xxxviii., 

 s. 212. 



