320 



post-morteni evidence of infarcti, such as Crevaux found in 50 per cent, 

 of the yellpw fever cadavers examined by him in French Guayana 

 (Archives de Méd. N avale, 1877, tome xxviii. p. 223.) 



The fourth condition has been satisfied every time I have attempted 

 it upon my inoculated rabbits, always recovering the tetracoccus. Moreover, 

 in the case of mild albuminuric yellaw fever which resulted after a 

 mosquito inoculation (as mentioned in the preceding paragraph), I was 

 able to recover the tetracoccus from the head and proboscis of a mosquito 

 which I had made to sting the patient during the attack. 



In view of the facts and arguments set forth in this paper, I consider 

 myself justified in regarding the pathogenicity of the tetracoccus versatilis 

 as experimentally proven, and in assuming that this microbe is the specific 

 germ of yellow fever, a conclusion already foreseen ever since my previous 

 investigations in collaboration wich Dr. Delgado in 1887. 



Before finishing, I beg to express my sincere thanks to our 

 distinguished colleagues, Dr. Santos Fernández, for the valuable resources 

 he has kindly placed at my disposal in the Laboratory of the Crónica-Mé- 

 dico-Quirúrgica, and to Dr. Davalos and to Dr. Acosta, for their effectual 

 assistance. 



Mosquito=Tetracoccus series (A to L) 1) 



A. Black rabbit — 840 grammes. March 14, 1895 — filtered 47 days' culture 



of mosquito-tetracoccus : 5 c. e. in peritoneum, and 5 c. c. 

 subcutaneously (=1/84). Died in the night of March 22, 

 weighing 630 gr. 



B. Black and white rabbit — 1000 grammes. March 22 — filtered 47 days' 



culture: 19 c. c. in peritoneum, and 9 c. c. subcutaneously 

 (=1/53). Died March 31, 8 a. m. ; weighed 740 gr. 



C. Bliack rabbit — 760 grammes. April 26, 2 p. m. — 10 e. c. (=1/74), live 



49 days' culture subcutan., 15 days' incubation; invasion May 11. 

 Died May 17, 1 p. m. ; weighed 590 gr. 



D. White rabbit— 650 grammes. May 18, 10 a. m.— 8 c. c. (=1/81). live 



6 days' culture tetracoccus from ear of C (May 1). Died May 25, 



2 p. mi. ; weighed 490 gr. 



E. Black and white rabbit — 750 grammes. May 26, 10 a. m. — 10 c. c. 



(=1/75), 48 hours' culture tetracoccus from ear of D (May 21). 

 Died June 2, night ; weighed 565 gr. 



F. Black rabbit — 590 grammes. June 6, 3 p. m. — 4 c. c. (=1/147), 25 



hours' culture tetracoccus from heart blood of E. Died June 15, 



3 p. m. ; weighed 430 gr. 



6. Black rabbit — 590 grammes. June 6, 3 p. m. — 5 c. c. (=1/118), 25 

 hours' culture tetracoccus from heart blood of E. Died June 14, 

 9 p. ml. ; weighed 435 gr. 



1) See chart, p. 303. 



