THE MOULD-FUNGI. 119 



the greatest interest as an indication of the existence of 

 unexpected gradations even in this natural domain. 



A certain amount of carbon dioxide and ethyl alcohol 

 is developed in liquids undergoing a Monilia fermentation. 



Finally, it is worthy of mention that this fungus is dis- 

 tinguished by its power of withstanding high temperatures. 

 In beer-wort and cane-sugar solutions it develops vigorously at 

 40 C., and induces an active fermentation at this temperature. 



7. OIDIUM LACTIS. 



A mould-fungus which has played an important part in the 

 literature of the physiology of fermentation and in that of 

 medicine is O'idium lactis, the so-called lactic acid yeast. 



Some authors have sought to establish the theory that this- 

 fungus is a stage in the development of species which, under 

 other circumstances, occur in entirely other forms, and with 

 quite different properties. It was thus brought into genetic 

 relation with Bacteria, Chalara (see below), Saccharomyces, 

 etc. Both BREFELD and HANSEN have carried out numerous 

 investigations with this fungus, and have undertaken culture 

 experiments, which were continued for a long time without 

 producing any other than the ordinary Oidium-form. Eecently, 

 it is true, BREFELD has discovered, in several higher fungi, a 

 formation of conidia resembling chains of O'idium cells ; but 

 it has not yet been determined whether this also includes that 

 particular species which we designate O'idium lactis. 



FRESENIUS correctly gave to this species the specific name of 

 lactis (of milk); for universal experience goes to show that it 

 has its ordinary habitat in milk, where it can be found, in the 



FIG. 3'2. Monilia Candida (after HANSEN): growth of mould ; forms like a are fre- 

 quent ; they consist of chains of elongated cells, more or less thread-like, and rather 

 loosely united ; at each joint there is generally a verticil of oval cells, which readily 

 fall off ; b represents another form, also of frequent occurrence, but distinguished 

 from the former by having no verticillate cells ; instead of these there generally issues 

 from every joint a branch of the same form as the mother cell, but shorter; the links 

 of these chains are often closely united, the constrictions in many cases disappear, 

 and a very typical mycelium, with distinct transverse septa (c) is produced ; the 

 forms b and <; occur in the nutritive medium, a commonly on the surface. Forms like 

 d have much resemblance to Oidiurn lactis. e shows a chain of pear-shaped cells with 

 verticils of yeast-cells resembling Sacch. exiguus ; the chain of lemon-shaped cells 

 represented at / closely resembles Ehrenberg's figures of O'idium fructigenum. 

 Between the principal forms described there are numerous yeast-cells of different 

 forms, variously arranged in colonies ; as is usually the case, there also appear forms 

 like Sacch. conglomeratus Reess. 



