341 



Translation: "The idea that you bring forward concerning blister- 

 serum is well founded. In animals immunized against tetanus and diphthe- 

 ria the serum of edema and of blisters has the same properties as the blood- 

 serum. M. Vaillard has made on this subject some very conclusive 

 experiments with animals immunized against tetanus. I wish you much 

 success in your attempts in yellow fever and shall be happy to know them." 



My modus operandi has been as follows: Having selected a person who 

 has recently passed through a well-marked attack of yellow fever, a 

 period of three or four weeks having elapsed since the last trace of albu- 

 minuria or fever has disappeared, I disinfect a portion of the skin of his 

 arm, forearm or upper part of his chest, in such a position that the forth- 

 coming blister may be protected against accidental rupture. I then apply 

 with a sterilized brush four or five layers (according to the thickness of the 

 skin) of the following preparation: 



Cantharidin (Merck's) 10 centigrams. 



Acetic ether and collodion, of each. ... 10 cubic centimeters. 



After the last layer has dried I place over it a piece of sterilized tissue- 

 paper and cover all with a thick pad of sterilized cotton, finally besmearing 

 the edges and the surface of the pad with simple collodion. A few turns of 

 gauze bandage are applied and the person is warned to keep the part at 

 rest so as to avoid accidental rupture of the blister. After 18 or 24 hours 

 the latter is uncovered, some of the serum is drawn into a sterilized hypo- 

 dermic syringe and a few drops (from 2 to 6 in my cases) are injected in 

 any convenient part of the person or persons to be inoculated. No reaction, 

 either local or general, has been observed in any of my cases. The blister 

 itself causes very little trouble beyond the necessity of watching it to 

 prevent rupture, and, covered with a simple antiseptic dressing, it will 

 heal in 2 or 3 days. 



I strongly recommend that should a case of yellow fever occur and the 

 patient recover, if he be free from specific taint, his acquired immunity be 

 utilized for the benefit of his companions in the manner that I have 

 described. 



When there is a choice, I consider it advisable to procure the serum 

 from persons having experienced the severest forms of the disease, so as 

 to obtain an immunity that may protect not only against the primary, but 

 also against the secondary infections, which contribute so much to the 

 danger of yellow fever. 



