172 G. G. Hesiop: 



In order to prove that a culture obtained by primary inocula- 

 tion of virulent serosity into Martin's broth plus ox serum, was 

 filtrable, the following experiment amongst others was under- 

 taken : — 



Two c.c. of a third sub-culture, from a culture which had been 

 obtained by primary inoculation of virulent serosity into tubes of 

 Martin's broth, plus ox serum, at the time that the post-mortem 

 examination was made, was diluted with 200 c.c.s., of Martin's 

 broth, without serum, and filtered through a Chamberland F. 

 filter. Fifteen c.c.s. of normal ox serum were then filtered 

 through the same filter into the same filtrate, and the final re- 

 sulting filtrate was well mixed and distributed into sterile test 

 tubes, and incubated at 37°C. Growth was apparent in 21 days. 

 This experiment — or another similar to it, differing only in the 

 quantities of broth, culture and serum employed (the ratio of 

 culture to broth in each instance never exceeding 1 to 100) — was 

 repeated later with a similar result, excepting that in the second 

 instance growth was not apparent until after 25 days' incuba- 

 tion at 37°C. These experiments prove that the organism ob- 

 tained in primary cultures by tube inoculations made at the post- 

 mortem is capable of passing through a Chamberland F. filter 

 when the culture is properly diluted with Martin's broth prior 

 to filtration. These experiments have also demonstrated another 

 important fact, namely, that while growth may be apparent in 

 from 4 to 6 days following a primary inoculation of virulent 

 serosity into Martin's broth plus ox serum at a post-mortem, 

 growth is not apparent until from 21 to 25 days after a filtration 

 experiment through Chamberland F. filter candles. The result- 

 ing growth in each instance, however, appears to have identical 

 characters. 



If the required quantity of serum is added to Martin's broth 

 before filtration of the virulent material, the organisms will not 

 pass through the filters. The Martin's broth used for diluting 

 the virus or culture prior to filtration should first be passed 

 through a Chamberland F. filter in order to facilitate the next 

 filtration when the virus of culture is added. It has been demon- 

 strated by my experiments, that a dilution of 1J c.c.s. of cul- 

 ture in 100 c.c.s. of previously filtered Martin's broth without 

 serum allowed the organism to pass through the filter, but in 

 another experiment, where 4 c.c.s. of the same culture was diluted 

 with 100 c.c.s., from the same bulk sample of Martin's broth, the 

 resulting filtrate was sterile. 



