896 PROTOZOA AND OTHER ANIMALS 



In 1923 Lwoff reported that he had succeeded in growing "Colpidium 

 colpoda" in pure culture, with neither hving nor dead microorganisms, 

 in a medium of peptone broth. He later revised the identification to 

 Glaucoma piriformis, and in 1932 considered it to be exceptional and 

 unique in its utilization of dissolved nutrient material only. Since then 

 some other ciliates have been maintained in sterile, non-particulate cul- 

 ture; but the number is limited, and some have turned out to be actually 

 G. pyriformis (Hetherington, 1936). 



It has been shown that G. pyriformis, when introduced into the 

 hemocoele of certain insects, multiplies rapidly and exhibits marked 

 pathogenic potentialities. Lwoff (1924) inoculated the ciliate from 

 pure culture into about thirty caterpillars of Galleria mellonella, all of 

 which succumbed to the infection in from eight to fifteen days. Shortly 

 before death, the blood contained no more leucocytes, but only great 

 numbers of ciliates invading all parts of the body. The ciliates nourished 

 themselves phagocytically at least in part, and contained many globules 

 of fat from the fat bodies of the caterpillar. 



Janda and Jirovec (1937) injected bacteria-free cultures of G. pyri- 

 forfuis into the body cavities of various invertebrates and vertebrates, and 

 also brought them into contact with artificially produced wounds. At- 

 tempts to infect annelids, molluscs, Crustacea, fish, and amphibia failed, 

 but many insects were successfully inoculated. The ciliates multiplied 

 so rapidly as almost completely to fill the hemolymph in a few days. 

 The fatty tissues especially were destroyed, the ciliates became larger 

 than normal, and the infected insects usually died in a few days. Infec- 

 tion through wounds was achieved only in the aquatic larvae of Aeschna 

 cyanea. Infection by mouth did not occur. Glaucoma that had been para- 

 sitic for some time when returned to the water survived and multi- 

 plied normally. 



It appears, then, that insects' blood is a favorable medium in which 

 G. pyriformis may grow, and that the tissues often provide no protec- 

 tion against the organism once it has entered. One would expect that 

 occasionally so common a ciliate might enter an aquatic insect through 

 an external wound or a damaged gut wall, and multiply in the same 

 way with disastrous consequences to the host. That has, indeed, been 

 found to take place. 



It is possible, as Wenyon (1926) suggested, that Lambornella 



