318 



Conclusions 



By comparing the results of the above-mentioned experiments with the 

 communications presented by Dr. Delgado and myself to this learned 

 Society in the course of the last nine years, it must be admitted that we 

 were not far wrong in the three conclusions we came to in a paper which 

 was published in La Enciclopedia of Dr. González (February 1877), viz: — 



"1. That the micrococcus tetragenus febris flava? is the characteristic 

 form of the microbe of yellow fever. 



"2. That the eulex mosquito is a known agent through which the 

 disease may be transmitted. 



"3. That, judging by our experiments (1887), it is possible to 

 protect non-acclimated subjects againts severe yellow fever by means of 

 our mosquito inoculations." 



The third of these conclusions does not properly belong to the subject 

 under consideration, though I look upon it as favourably decided by the 

 fact that of one hundred presumably susceptible persons who have received 

 the mosquito inoculation during the last fourteen years, only three have 

 subsequently died of yellow fever. 



in order to prove the second proposition, it would be sufficient to 

 demostrate the first, — i.e. that the "tetracoccus versatilis" is the germ of 

 yellow fever; the identity of the mosquito tetracoccus and the yellow fever 

 tetracoccus having been shown. 



"We must now consider if our germ fulfils the conditions demanded by 

 Koch for the acceptance of a micro-organism as the cause of a disease, 

 viz. — (1) That it be found in the liquids and tissues of those attacked 

 with the disease; (2) that it be isolated in pure cultures; (3) that the 

 disease be reproduced by inoculation; (4) that the microbe be recovered 

 from the inoculated subjects. 



The first of these conditions implies the presence of the tetracoccus in 

 yellow fever patients. Prom the examples cited in this paper can readily 

 be seen the facility with which the tetracoccus may be obtained from a tiny 

 drop of blood drawn from the finger of a patient, under the conditions 

 which I have pointed out. To this the opponents of my former ' ' tetragenus ' ' 

 will probably object that my sterilization of the skin is insufficient, and 

 that the germ obtained proceeds from the skin and not from the blood ; but 

 if this were true, it would be extremely unlikely that any pure culture of 

 a given microbe could be thus obtained, and when the tetracoccus did not 

 develop, some other microbe would have done so; whereas my tubes planted 

 with finger blood have generally given pure tetracoccus cultures, and those 

 in which this has not germinated have remained completely sterile. Dr. 

 Sternberg himself is satisfied that he has found my "tetragenus" upon 

 the skin of the generality of yellow fever patients examined by him in 

 Vera Cruz and in Havana, and I remember that in one of my agreeable 

 "causeries" with this distinguished bacteriologist, he employed against 



