E. Iavanow 319 
penetrating through intact mucous membranes, it would be very difficult to 
explain such facultative infectibilitv. 
I have not repeated the experiments on inoculation of the mucous mem¬ 
branes of the eye, vulva, or of the skin, and I should not be surprised, if 
infection was produced by such methods, since the mucous membranes of 
the external organs and even the skin are easily exposed to slight, hardly 
visible wounds, which, however, are sufficient for the parasite to penetrate. 
That is why I choose the vagina for my experiments, since this is an 
organ the mucous membrane of which is protected from external irritations 
likely to cause wounds (with sand, hay, dust), and at the same time it is 
accessible for experimental purposes. Of course, in this case it may also 
happen that tbe introduction of T. equiperdum into the vagina produces 
infection, even when the above precautions are taken, e.g. if the female is 
used soon after parturition or with its external genitals injured, or after coitus 
which has left traces in the form of light abrasions. 
In my experiments objection may be taken to the fact that when the 
catheter is smeared with vaseline and introduced into the vagina, the vaseline 
may form a coating isolating the mucous membrane. When, however, the 
infection was introduced into control mice whose vaginal membrane was 
previously abraded, I also smeared the catheter with vaseline, and this did 
not prevent the infection and death of the mice. 
In the light of my observations on the method of infection with Dourine, 
in combating this disease, which causes such ravages in the stud-farms not 
only of Russia, but of Canada and other countries as well, attention should 
first of all be directed to the methods of preventing possible wounds and 
abrasions on the mucous membranes of the genital organs of horses during 
coitus. 
This can be attained in the following way. Horses should not be allowed 
to breed promiscuously in the herd, but should be covered individually under 
control, which allows of taking care that the external genital organs are clean 
during coitus, that the penis does not get scatched by the hairs of the mare’s 
tail. The external genitals of the mare should be washed and her tail carefully 
dressed before the act. Then, to facilitate coitus it is advisable to lubricate 
the external genitals of the mare and the penis of the stallion with vaseline 
or oil. 
21—2 
