986 PROTOZOA AND OTHER ANIMALS 



by ciliates. Separating by filtration the ciliate, bacterial, and food frac- 

 tions, he fed each to pigeons, together with polished rice. He concluded 

 that it is extremely improbable that the ciliate fauna has the capacity 

 of synthesizing vitamin B. The bacterial fraction proved to be the most 

 antiberiberic. 



Becker was the first to carry on the obvious experiments which should 

 be made in investigating the significance of the ciliates to their hosts. 

 That is defaunation, which led to such dramatic results in Cleveland's 

 work with termites. If the ciliates perform any necessary function, the 

 effect should become apparent in animals deprived of them. Becker, 

 Schulz, and Emmerson (1930) defaunated four goats, and for periods 

 of two and three weeks made detailed analyses of their use of nutrients. 

 The goats were then reinfected, and after ten days analyses were con- 

 tinued for the same period as before. The presence or absence of ciliates 

 was accompanied by little difference in the coefficients of digestibility. 

 There were no differences of practical significance in the digestion of 

 cellulose, and the goats with ciliates used only slightly more protein 

 than those without. Winogradow, Winogradowa-Fedorowa, and Wer- 

 eninow (1930) had found that raw fiber was 12.8 percent better digested 

 in a normally faunated than in a ciliate-free ram. 



Becker and Everett (1930) compared during nineteen weeks the 

 growth of seven lambs with ciliates and seven without, the Protozoa 

 having been removed by giving some lambs copper sulphate with milk. 

 They found that the defaunated lambs actually grew a little more rapidly 

 than the others. 



Poljansky and Strelkow (1935) made observations on growth of four 

 pairs of twin goats for ten months, beginning at the age of from one 

 to two and a half months. The goats were isolated from the parents so 

 early that they did not become naturally infected. One member of each 

 pair was given a ciliate population. In this experiment, also, the ciliate- 

 free goats of three pairs grew a little faster than the others; in one pair 

 the goat with ciliates gained more. 



Falaschini (1935) compared for a period of fourteen months the 

 growth of four lambs. Two were defaunated by a milk diet after six 

 months, then in five weeks reinfected with ciliates. The other two were 

 defaunated after eight months, then continued on a normal diet with- 

 out ciliates. The growth curves of the four lambs corresponded. 



