62 THE PERMANENT FORMS, OR SPORES. 



boiled infusions of hay; and as a matter of general interest an 



example from the pathogenic bacteria may be cited, viz., Bacillus 



tetani, by which tetanus is produced. 



Not inferior in number are the species wherein the sporogenic 



rod ordinarily swells up in the middle and gives rise to a spindle- 

 shaped outline resembling that 

 of a lemon or cop of yarn. 

 TRECUL(!.), who in 1865, in the 

 course of his studies in butyric 

 fermentation, first became ac- 

 quainted with this bacterial 

 form, gave it the name of 

 Clostridium, a term adopted as 

 a generic name by Prazmowski. 

 The two species described by 

 this worker, viz., Clostridium 

 butyricum, (Fig. 16) and Cl. 

 FIG. i 7 .-Baciiius inflates. Polymyxa, were supplemented 



Spore formation. b LlBORIUS (I.) with Clostri- 



a. b. e. cells of Clostridium form, each 7 /? , . / * * 



containing one elongated cylindrical MW foetldum, a fission fungUS, 



&SS^^^i^2%S T hich i V sola * ed from ^ 



Magn. 2100. cheese, and produces a repel- 



lent odour in artificial nutrient 



media. A fourth species is the Bacillus alvei, discovered by 

 CHESHIRE and CHEYNE (I.), which causes the so-called "foul 

 brood" in bees. The Bacillus inflatus (Fig. 17), discovered by 

 ALFRED KOCH (I.) in 1888, also belongs hereto. Beyerinck in- 

 vestigated the conditions under which the Clostridium form is 

 assumed by a number of species, having close affinities with 

 Clostridium butyricum, which have been grouped under the genus 

 Granulobacter. 



50. The Number of Spores 



produced in a single mother-cell exceeds unity in but few species. 

 The first communication on this subject was made by Prazmowski, 

 who found that in exceptional cases Clostridium butyricum de- 

 veloped two spores in a cell. A representation of this is given 

 in Fig. 1 6. ED. KERN (I.) observed in Caucasian Jcephir granules 

 a bacillus to which, on account of its faculty of producing two 

 spores, the name of Dispora caucasica has been given. This 

 bacillus produces a spore at each of its two poles, without any 

 alteration of size or shape being undergone by the latter. 

 The contrary report, met with in many books, viz., that this 

 microbe during spore-formation swells up in such a manner that 

 it assumes the form of a dumb-bell, is a pure invention. The 

 doubt raised by MACE (I.) in 1889, and shared by many others, 

 against the sporous nature of this form, is also groundless, since 



