The best short article by James Hogg on the topic of Carthusian total 
abstinence from meat and whether this was too extreme is probably 
"Carthusian Abstinence" in _Spiritualitaet Heute und Gestern_, part 14 (= 
Analecta Cartusiana, vol. 35.14) (Salzburg: Institut fuer Anglistik und 
Amerikanistik, 1991), pp. 5-15.  He deals with the treatise by Arnold of 
Villanova, "Contra illos qui dicunt Cartusienses peccare non ministrando 
carnes infirmis suis" on p. 8, with appropriate references (since Arnold 
was a physician, his treatise carried extra weight.  Gerson's De non esu 
carnium apud carthusienses is found in the Glorieux edition, vol. 3, pp. 
63-77.  Hogg's article contains extensive quotations from the Carthusian 
general chapter on this topic and his typical store of anecdotes.

Hogg has published on an earlier treatise by Guillelmus de Yporegia 
(d'Ivree) defending the Carthusians against similar charges (1310).  See 
Hogg, "Guillelmus de Yporegia: De Origine et veritate perfecte 
religionis" in Analecta Cartusiana, 82, part. 2 (1980), pp. 84-118.

Since the Analecta series is not easily accessible (beware of confusing 
this more-or-less monograph series with the semi-annual journal of the 
same name, published in France from about 1990-1994, sometimes 
referred to as Analecta Cartusiana, n.s.), one might take note 
of Hogg's article "Everyday Life in the Charterhouse of the Fourteenth 
and Fifteenth Centuries," in _Kloesterliche Sachkultur des 
Spaetmittelalters_, Interntionaler Kongress Krems an der Donau, 18. bis 
21. September 1978 (Vienna: Oesterreichische Akademie der Wissenschaften, 
1980), 113-46 and "The Carthusians and the Rule of St. Benedict" in 
_Itinera Domini: Gesammelte Aufsaetze aus Liturgie und Moenchtum_: 
Festschrift Emmanuel von Severus O.S.B._  (Muenster: Aschendorff, 1988), 
281-318.  I am relying on memory here, but I think these articles adress 
the question of relaxation of the original Carthusian strictness.

One might also consult the indexes to Albert Gruijs, _Cartusiana: Un 
Instrument Heuristique_, 3 vols. (Paris: CNRS, 1976-78).  An updated, 
comprehensive bibliography of Cartusiana is being prepared by Jan de 
Grauwe and should be published in the near future.

Finally, it might be of interest to know that within the last decade, a 
group of Carthusians left the charterhouse of Montrieux in southern 
France in an effort to return to a more extreme rigor along the lines of 
the very first Carthusian hermits in the mountains above Grenoble, before 
the Carthusian Order came into existence.  This group of four or five men 
has established a very primitive hermitage near the village of Parisot.  
A description of their life is found (again by the inimitable James Hogg) 
in "A Visit to the Parisot "Carthusians" in the Easter Week of 1993,"
in _Die Kartaeuser und ihre Welt: Kontakte und gegenseitige Einfluesse_, 
Analecta Cartusiana, vol. 62, part. 3 (Salzburg, 1993), pp. 235-54 (about 
half the article consists of photographs).

Dennis Martin
Loyola University Chicago