772 EXPERIMENT STATION KECOED. 



" a variety of acid-fast bacteria, including various strains of the human tubercle 

 bacillus, the bovine, and avian tubercle bacilli, as well as the leprosy, smegma, 

 and grass bacilli, form lipase during their growth in glycerin broth. The 

 lipase is present in the medium free from the bacteria. The lipase resists an 

 exposure of 15 minutes to 100° C. in the moist state without appreciable diminu- 

 tion in its activity. The lipase formed by these organisms appears to be non- 

 diffusable, at least in an active state, through either agar or a collodion 

 membrane." 



In the seventh study on the relative activity of the soluble lipase and lipase 

 liberated during autolysis of certain rapidly-growing tubercle bacilli, it is stated 

 that " the observations appear to justify the conclusion that certain acid-fast 

 bacteria grown in nutrient broth, with dextrose, mannit, and glycerin as addi- 

 tional sources of carbon, produce an active lipase which appears in solution 

 in the various culture media. The bodies of the bacteria, freed from adherent 

 culture media and soluble lipase by thorough washing, also contain an active 

 lipase, probably liberated as the bacteria underwent autolysis. The lipa.se in 

 solution appears to be either greater in amount or more active than that con- 

 tained in the bacteria freed from the culture medium. It can not be stated 

 whether the lipase free in the culture media is freed as the result of autolysis 

 of the bacterial cells (endolipase), or whether it is secreted by the bacteria as 

 an exolipase." 



In the eighth study on the specificity and thermostability of the lipase 

 developed during the gi'owth of a rapidly-growing tubercle bacillus in media 

 of varied composition it was concluded that " a rapidly-growing strain of the 

 human tubercle bacillus produces a lipase which appears to be qualitatively the 

 same when it is grown in media varying in composition from one consisting 

 essentially of ammonium chlorid, ethyl alcohol, NazHPOi, and NaCl to the 

 extremely complex nutrient meat-juice-peptone broth ordinarily used for bac- 

 terial cultures. The lipase observed in the simplest media acts on various 

 esters, irrespective of the nature of the carbon compound of the medium in 

 which it is developed. For example, the lipase developed in the (NH4)2HP04 

 mannit medium acts on triacetin and castor oil as energetically as on ethyl 

 butyrate or other simple esters. That is to say, the lipase developed in the 

 simplest medium acts even on a complex glycerid. This lipase appears to be 

 thermostabile whether it is tested in the simplest media or in the most complex. 

 The activity of the lipase appears to be roughly proportionate to the relative 

 luxuriance of the growth of the tubercle bacillus." 



By the ninth study, a comparison of the curves of lipolytic activity and 

 proteolysis of certain rapidly-growing human tubercle bacilli in media of varied 

 composition, it is shown that " the period of maximum vegetative activity of 

 broth cultures of certain avirulent, rapidly-growing tubercle bacilli, as measured 

 by ammonia formation (proteolysis), appears to coincide with the period of 

 maximum lipolytic content of these cultures, as measured by their action on 

 ethyl butyrate. Both ammonia production and lipolytic activity are extremely 

 slight during the first day's growth of these organisms, and increase, roughly, 

 proportionately to their respective maxima. There is a noteworthy recession 

 of both factors after this maximum is reached. These experiments appear to 

 warrant the assumption that the organisms studied excrete a soluble, active 

 lipase during the period of active development ; for if autolysis alone were 

 responsible for the lipolytic activity observed in these cultures, it should 

 increase as autolysis proceeds." 



The tenth study was a comparison of the curves of lipolytic activity and 

 proteolysis of certain acid-fast bacilli in nutrient broths. It showed that " in 

 general, with the exception of the ' lepra bacillus,' the acid-fast bacteria dis- 



