48 PROTOZOA AND DISEASE 



other organisms, produced Guarnieri's bodies. They are specific, 

 and may be used as a certain means of diagnosis in doubtful cases 

 of small -pox, and as a reliable test of the activity of any sample of 

 vaccine. They can be inoculated from eye to eye indefinitely. 

 From such vaccinated corneae typical vaccinations were made in the 

 fifteenth and twenty-fifth generations. From a small quantity of 

 corneal epithelium, rubbed up with bouillon, obtained by scraping 

 a cornea which represented the thirty-sixth generation, six out of 

 seven children were successfully vaccinated, the epithelial scraping 

 having been previously found to be free from bacteria by cultures 

 on agar, blood-serum, and in bouillon. 



Wasielewski also found that the cytoryctes increased in size 

 and developed a nucleus. In France F. J. Bosc showed that bodies 

 in many respects similar to cytoryctes are present in sheep-pox, and 

 also that similar forms occur in cancer. Bosc also described the im- 

 portant intranuclear forms almost at the same time as the American 

 observers, 1 Councilman, Magrath, and others, who were aided by 

 Professor G. N. Calkins, whose eminence as a biologist has im- 

 pressed his fellow-biologists with the importance of the subject. 

 Some of the chief points in the results obtained by the American 

 observers, as digested by the biological knowledge and experience 

 of Calkins, I referred to in opening a discussion at Glasgow in 

 I9O4/ 2 I then said : ' Calkins believes that in variola these bodies 

 are parasites, and the difference between vaccinia and variola con- 

 sists in this : that in the former they have only a cytoplasmic habitat 

 and a vegetative (multiplicative) process of reproduction, whilst, in 

 addition to this, in variola there is an intranuclear stage, where, 

 probably, sexual interchange followed by sporing (propagative repro- 

 duction) occurs. I have been able to recognise the chief forms that 

 Calkins and his co-workers have described. Some of the various 

 forms figured by Calkins are reproduced in'^Fig. 13 ; /to 9. They are 

 very abundant in the lesions, and I have been able to identify the 



1 The first description of these appeared in the form of a preliminary note in 

 the Journal of Medical Research, 1903. The full account appeared later in the 

 same journal, and is reprinted as a separate volume. 



- The Journal of the Royal Sanitary Institute, part iii., 190-;. 



